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., Chapter 6 Bosch Motronic MPi (35, 55 & BB-pin types) Contents Overview of system operation Catalyticconverter and emission control. . . . . . . . . . . . . . . . . . . .. 6 Control functions. ....................................... 2 Fuel injection (MPi) ....................................... 5 Introduction. ........................................... 1 Primaryand secondary ignition. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4 Primary trigger. ......................................... 3 Adjustments Adjustment pre-conditions 7 Idle adjustments. ....................................... 10 Ignitiontimingchecks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9 Throttle adjustments. .................................... 8 System sensor and actuator tests Air temperature sensor (A TS) ............................... 18 Airflow sensor (AFS) ..... : ................................ 16 Carbon filter solenoid valve (CFSV) .....-..................... 28 CO potentiometer ('pot') 19 Coolant temperature sensor (CTS) 20 Crank angle sensor (CAS) 11 Specifications Vehicle BMW, Motronic First Generation 325i non-cat. ............................................. 325e.cat. ................................................ 525e non-cat. ............................................ 525e .::at ................................................. 525e non-cat .~ . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . 535i/M535i non-cat. ....................................... MS DOHC non-cat. ..... ',' ................................. BMW, Motronic 1.'3 316/318/518i non cat. ...................................... 316/318/518i cat. ! ......................................... 320/325i non cat. ....................................... . .. 320/325i cat. ............................................. 520/525i non cat. .......................................... 520/525i cat. ............................................. 530/535i non cat. .......................................... 530/535i cat. .............................................. BMW, Motronic 1.7 316icat................................................. 316i&Compact. . . . . . . . . . . .. . . . . . . . . . .. . . . . . . .. . . . . . . . . . . . 318is 16V cat. ............................................ 318i cat. ................................................ 318is &Compact. ......................................... 318i .,. 518i ........................... 750i & L & cat. ............................................ 850i ..................................................... ECM voltage supplies and earths. .......................... 24 Fuel injector operation. ................................... 14 Fuel pressure. .......................................... '26 Hall-effect phase sensor (CID, GM 16-valve engines) ............ 15 Idle speed control valve (ISCV) 23 Knock sensor (KS) ....................................... 13 MAP sensor. ........................................... 17 Oxygen sensor (OS) ...................................... 27 Primary ignition. ........................................ 12 System relays. ......................................... 25 Throttle potentiometer sensor (TPS) 22 Throttle switch (TS) 21 Pin table - typical 35-pin (First Generation Motronic, BMW) Pin table - typical 35-pin (Motronic 3.1, Citroen/Peugeot) Pin table -typical 55-pin (Motronic 1.5, Vauxhall) Pin table - typical 88-pin (Motronic MP3.1, BMW) Fault codes . Obtaining fault codes. .................................... 29 I .! Year Idle speed CO% 1985 to 1986 760 :I:40 0.7:1: 0.5 1985 to 1991 700 :I:50 0.5 max 1983 to 1985 700 :I:50 1.0:1: 0.5 1986 to 1987 720 :I:40 0.5 max 1986 to 1987 720 :I:40 1.0:1: 0.5 1982 to 1986 800 :I:50 1.0 :I:0.5 1985 to 1987 850 :I:50 1.5 max 1988 to 1991 800 :I:40 0.7 :1:0.5 1988 to 1991 800 :I:40 0.5 max 1986 to 1991 760 :I:40 0.7:1: 0.5 1986 to 1991 760 :I:40 0.5 max 1988 to 1991 760 :I:40 0.7:1: 0.5 1988 to 1991 760 :I:40 0.5 max 1988 to 1991 800 :I:50 0.7 :I:0.5 1988 to 1991 800 :I:50 0.5 max 1991 to 1993 800 :I:40 0.7:1: 0.5 1993 to 1996 800 :I:40 0.7:1: 0.5 1990 to 1991 850 :I:40 0.7 :1:0.5 1991 to 1993 800 :I:40 0.7:1: 0.5 1992 to 1996 850 :I:40 0.7:1: 0.5 1993 to 1996 800 :I:40 0.7 :1:0.5 1993 to 1996 800 :I:40 0.7:1: 0.5 1987 to 1994 700 :I:50 0.7 :I:0.5 1991 to 1994 700 :I:50 0.7:1: 0.5
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Page 1: Bosch Mo Tronic

.,

Chapter 6Bosch Motronic MPi (35, 55 & BB-pin types)ContentsOverview of system operationCatalyticconverter and emission control. . . . . . . . . . . . . . . . . . . .. 6Control functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2

Fuel injection (MPi) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1

Primaryand secondary ignition. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4Primary trigger. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3

AdjustmentsAdjustment pre-conditions 7Idle adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Ignitiontimingchecks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9Throttle adjustments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8

System sensor and actuator testsAir temperature sensor (ATS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Airflow sensor (AFS) . . . . . : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Carbon filter solenoid valve (CFSV) . . . . .-.. . . . . . . . . . . . . . . . . . . . 28

CO potentiometer ('pot') 19Coolant temperature sensor (CTS) 20Crank angle sensor (CAS) 11

SpecificationsVehicle

BMW, Motronic First Generation325i non-cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .325e.cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .525e non-cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .525e .::at .................................................525e non-cat . ~. . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . .535i/M535i non-cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MS DOHC non-cat. . . . . . ',' . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . .

BMW, Motronic 1.'3

316/318/518i non cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .316/318/518i cat. ! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .320/325i non cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .320/325i cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .520/525i non cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .520/525icat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .530/535i non cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .530/535i cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . .

BMW, Motronic 1.7

316icat.................................................316i&Compact. . . . . . . . . . . .. . . . . . . . . . .. . . . . . . .. . . . . . . . . . . .318is 16V cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .318i cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .318is &Compact. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .318i .,.518i ...........................750i & L & cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .850i .....................................................

ECM voltage supplies and earths. . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Fuel injector operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Fuel pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . '26Hall-effect phase sensor (CID, GM 16-valve engines) . . . . . . . . . . . . 15

Idle speed control valve (ISCV) 23Knock sensor (KS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

MAP sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Oxygen sensor (OS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Primary ignition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

System relays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Throttle potentiometer sensor (TPS) 22Throttle switch (TS) 21Pin table -typical 35-pin (First Generation Motronic, BMW)Pin table -typical 35-pin (Motronic 3.1, Citroen/Peugeot)Pin table -typical 55-pin (Motronic 1.5, Vauxhall)Pin table - typical 88-pin (Motronic MP3.1, BMW)Faultcodes .

Obtaining fault codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

I.!Year Idle speed CO%

1985 to 1986 760 :I:40 0.7:1: 0.51985 to 1991 700 :I:50 0.5 max1983 to 1985 700 :I:50 1.0:1: 0.51986 to 1987 720 :I:40 0.5 max1986 to 1987 720 :I:40 1.0:1: 0.51982 to 1986 800 :I:50 1.0 :I:0.51985 to 1987 850 :I:50 1.5 max

1988 to 1991 800 :I:40 0.7 :1:0.51988 to 1991 800 :I:40 0.5 max1986 to 1991 760 :I:40 0.7:1: 0.51986 to 1991 760 :I:40 0.5 max1988 to 1991 760 :I:40 0.7:1: 0.51988 to 1991 760 :I:40 0.5 max1988 to 1991 800 :I:50 0.7 :I:0.51988 to 1991 800 :I:50 0.5 max

1991 to 1993 800 :I:40 0.7:1: 0.51993 to 1996 800 :I:40 0.7:1: 0.51990 to 1991 850 :I:40 0.7 :1:0.51991 to 1993 800 :I:40 0.7:1: 0.51992 to 1996 850 :I:40 0.7:1: 0.51993 to 1996 800 :I:40 0.7 :1:0.51993 to 1996 800 :I:40 0.7:1: 0.51987 to 1994 700 :I:50 0.7 :I:0.51991 to 1994 700 :I:50 0.7:1: 0.5

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6-2 Bosch Motronic MPi (35, 55 and BB-pin types)

Vehicle

BMW, Motronic 3.1320i 24V cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .320i 24V .................................................325i 24V cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .325i 24V .................................................520L&-.Touring 24V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .520i & Touring 24V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .525i & Touring 24V ... . . . . . .. . . . . . .. . . . . . . .. . . .. .. . . . .. .525i & Touring 24V ... . . . . . .. . . . . . .. . . . .. . ... . .. . ... . . ... .. .

BMW, Motronic 3.3

530i&TouringV8 . . . . . . . . . . . . . . . . . . . . .540iV8 .................................................MS ......................................................730i V8 cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .730i .....................................................740i iL V8 ................................................740i .....................................................840Ci ...................................................

I

:1

CitroenlPeugeot, Motronic 1.3Citroen BX19, ZX19 (8V), BX19 (16V) (M1) . . . . . . . . . . . . . . . . . . . . . . .Citroen BX19, ZX19 (8V), BX19 (16V) (A1) .......................Peugeot 205/309/4051.9 (8V)(M1) ............................Peugeot 205/309/405 1.9 (8V)(A1) . . . . . . . . .. . . . . . . .. . .-. . . . .. .. .Peugeot 309/405 (16V)(M1) . . . . . . . . . .. . . . . . .. . . . .. .. . . . .. . .. .

CitroenlPeugeot, Motronic 3.1AX 1Ai K6B (fU3J2/K) ......................................AX 1Ai cat KFZ (fU3J2IL.Z). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BX 1.9i XU9J2 (D6D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ZX 1.9i XU9JA/K (D6E) ......................................XM 2.0i XU10J2Z (RFi) cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 1Ai TU3FJ2 (K6B) ......................................1061.4icatTU3FJ2(KFZ)...................................4051.9i(XU9J2)D6D . . . . . . . . . . . . . . . . . . . . . . . . . . . .605 2.Oi (XU10J2Z)RFZ cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CitroenlPeugeot, Motronic 3.2Xantia 2.0i 16V cat RFY (XU1 OJ4D/Z) . . . . . . . . . . . . . . . . . . . . . . . . . . .ZX2.Oi16Vcat RFY/RFT(XU10J4D/Z).........................306 2.0i16V cat XU1OJ4/Z(RFY) ..............................405 2.0i 16V cat XU1 OJ4/Z (RFY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CitroenlPeugeot, Motronic 4.1Citroen BX19 .............................................Peugeot 405 ..............................................CitroenlPeugeot, Motronic 5.1

.. Xantia LX/SX & Break 1.8i8Vcat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Xantia 2.0i 16V & Break XU10J4RUZlL3 (RFV) ...................XM2.0i16Vcat. ... ... . ... . . .. . .. . . .. . . .. . . . .. . " . .. . . . .. ..ZX 1.8i Advantage, Aura, Furio cat. . . . . . . . . . . . . . . . . . . . . . . . . . . . .3061.6i XL/XR/XS/XT, 1.8i cat XU7JP/z (LFZ). . . . . . . . .. . .. . . . ....405 2.0 XU7JPLIZ (LFZ) .....................................605 SU 2.Oi16V

VauxhalVOpel, Motronic 1.5C16SEI, MT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20SEH MT 4x4 ............................................C20NEMT4x4 .............................................C24NE, MT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C24NE, AT ...............................................C26NE ..................................................C30NE ..................................................C30SE, SEJ ..............................................All other models not listed above. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

II.I:II

:1'.

..

Year

1991 to 19931993 to 19961991 to 19931993 to 19961990 to 19931993 to 19961990 to 19931993 to 1996

1993 to 19961993 to 19961986 to 19881992 to 19941994 to 19961992 to 19941994 to 19961993 to 1996

1990 to 19911991 to 19961990 to 19921991 to 19921990 to 19921991 to 19921991 to 19961990 to 19921990 to 1995

1993 to 19951993 to 19951994 to 19961992 to 1995

1993 to 19961995 to 19961994 to 19961993 to 19961993 to 19961992 to 1996

Idle speed CO%

700:f: 40 0.7:f: 0.5700:f: 40 0.7 :f: 0.5700:f: 40 0.7 :f: 0.5700:f: 40 0.7:f:0.5800:f:40 0.7 :f:0.5700 :f:40 0.7 :f:0.5800 :f:40 0.7:f: 0.5700 :f:40 0.7:f: 0.5

600 :f:50 0.7 :f:0.5600 :f:50 0.7 :f:0.5850 :f:50 0.3 to 1.5600 :f:50 0.7 :f:0.5600 :f:50 0.7 :f:0.5600 :f:50 0.7:f: 0.5600 :f:50 0.7:f: 0.5600 :f:50 0.7:f: 0.5

850 to 950 0.8 to 2.0 (non-cat) 10.5 (cat)800 to 850 0.8 to 2.0 (non-cat) 10.5 (cat)850 to 950 0.8 to 2.0 (non-cat) 10.5 (cat)800 to 850 0.8 to 2.0 (non-cat) 10.5 (cat)850 to 950 0.8 to 2.0 (non-cat) 10.5 (cat)

880 1.0:f: 0.5900 :f:50 0.5 max850 :f:50 1.5:f: 0.5850 :f:50 1.5 :f:0.5875 :f:25 0.5 max920 :f:50 1.0 :f:0.5920 :f:50850 to 900 1.5:f: 0.5800 :f:20 0.5 max

880 :f:50 0.4 max880 :f:50 0.4 max850 :f:50 0.5 max880 :f:50 0.5 max

850 0.8 to 1.5830 to 930 1.5 to 2.0

850 :f:50 0.4 max800 :f:50 004max800 :f:50 004max850 :f:50 0.4 max850 :f:50 004max850 :f:50 0.4 max

820 to 980 1.0890 to 990 1.0890 to 990 1.0820 to 880 1.0720 to 780 1.0670 to 830 1.0670 to 830 1.0570 to 730 1.0720 to 780 1.0

Page 3: Bosch Mo Tronic

Bosch Motronic MPi (35, 55 and BB-pintypes) 6-3

Vehicle

Vauxhall/Opel, Motronic 2.5Allnon-cat models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Allcat .models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vauxhall/Opel, Motronic 2.7CavalierTurbo cat C20LET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vectra-ATurbo cat C20LET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Calibra Turbo 4x4 C20LET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vauxhall/Opel, Motronic 2.8Cavalier2.5i 24VC25XE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vectra-A2.5i 24VC25XE ....................................Calibra 2.0 16V & 4x4 C20XE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Calibra2.5i 24VC25XE .....................................Calibra2.5i 24VX25XE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Vauxhall/Opel, Motronic 2.8.1Omega-B2.5i X25XE .......................................Omega-B3.0i X30XE .......................................

Vauxhall/Opel, Motronic 2.8.3Vectra-B 2.5i V6 24V X25XE~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Year

1993 to 19951993 to 19951992 to 1996

1993 to 19951993 to 19951993 on1993 to 19961997

1994 to 19971994 to 1997

1995 to 1997

Vauxhall/Opel, Motronic 4.1Allvehicles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Volvo, Motronic740 and 760 Turbo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1985 to 1989

Overview of system operation

1 Introduction

Please read this overview of Motronicoperation in conjunction with Chapter 2,which describes some of the functions inmore detail.

The name 'Motronic' describes a family ofEMS's that first saw light of day in the early1980's. Motronic was one of the very first trueEMS's, and evolved from the well-tried 'L' and'LE' Jetronic fuel injection systems which firstemerged in the mid 1970's. Motronic hasevolved considerably over the years, and isnow fitted to a wide range of Europeanvehicles.

When fitted to BMW vehicles, Motronic issometimes labelled 'DME' (Digital MotorElectronics). Interestingly, the term DME isgenerically applied to most versions of theMotronic family fitted to BMW cars, and doesnot label any particular Motronic system.Currently there exists a variety of differentMotronic versions; First Generation, 1.5, 1.7,1.8,2.5, 2.7, 2.8, 2.8.1, 2.8.3, 3.1, MP3.1, 3.2,4.1, 5.1, 5.1.1, etc (see illustration 6.1).

We can basically divide Motronicdescriptions into Motronic 'First Generation'and Motronic MPi. Differences will be detailedunder these headings where descriptionsdiffer.

' 6 -].\i

10(": ...1

6.1 Typical Motronic system (1.5.2)

1 AFS 2 ATS 4 ISCV(airmass type) 3 TPS 5 Distributor

6 CFSV7 CTS

Idle speed CO%

860 to 1020 0.7 to 1.2 max860 to 1020 0.4 max

860 to 1020 0.3 max860 to 1020 0.3 max860 to 1020 0.5 max

620 to 780 0.3 max620 to 780 0.3 max860 to 1020 0.3 max620 to 780 0.5 max620 to 780 0.5 max

570 to 730 0.5 max570 to 730 0.5 max

570 to 730 0.3 max

720 to 780 1.0

800 to 850 0.5 to 2.0

Page 4: Bosch Mo Tronic

6-4 Bosch Motronic MPi (35, 55 and BB-pin types)

Motronic 'First Generation'A 35-pin connector and multi-plug

connects the First Generation Motronic ECMto the battery, sensors and actuators. FirstGeneration systems were mainly fitted from1985 to 1987, and are characterised byseparate RPM and TOC sensors. All latermodels utilise a single CAS.

Motronic MPiA 35-pin, 55-pin or 88-pin connector and

multi-plug connects the Motronic ECM to thebattery, sensors and actuators. Motronic 4.1utilises a 35-pin multi-plug. Motronic 1.7 andMP3.1 utilises a 88-pin multi-plug and theignition is OIS in operation. All the others,including 3.1, utilise a 55-pin multi-plug.

2 Controlfunctions

. jlj

GeneralMotronic normally controls primary ignition,

fuelling and idle speed in the vehicles to whichit is fitted. An automatic ISCV is directlyactuated by the Motronic ECM to maintain astable idle speed under all conditions of idleload. This is true of all late versions.

However, in some early First Generationsystems, the ISCV is actuated by a separateIdle control ECM. Alternatively, an coolant-controlled AAV, not actuated by the MotronicECM, is utilised.

The ignition point and injection duration arejointly processed by the Motronic ECM so thatthe best moment for ignition and fuelling aredetermined for every operating condition.

J

It

JI

,

~I

~I.fl

!I

Signal processingBasic ignition timing is stored by the ECM

in a three-dimensional map, and the engineload and speed signals determines theignition timing. The main engine load sensor iseither an AFS or a MAP sensor, and enginespeed is determined from the CAS signal.

Correction factors are then applied forstarting, idle, deceleration, and part- and full-load operation. The main correction factor isengine temperature (CTS).Minor correction totiming and AFR are made with reference tothe ATS and TPS or TS signals.

The basic AFR is also stored in a three-dimensional map, and the engine load andspeed signals determine the basic injectionpulse value. Motronic calculates the AFR fromthe load signal and the speed of the engine(CAS).

The AFR and the pulse duration are thencorrected on reference to ATS, CTS, batteryvoltage and position of the TPS or TS. Othercontrolling factors are determined byoperating conditions such as cold start and

.warm-up, idle condition, acceleration anddeceleration.

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Motronic accesses a different map for idlerunning conditions, and this map isimplemented whenever the engine speed is atidle. Idle speed during warm-up and normalhot running conditions is maintained by theidle control (not First Generation). Motronicalso makes small adjustments to the idlespeed by advancing or retarding the timing,and this results in an ignition timing value thatis forever changing during engine idle.

Basic ECM operation (typical)A permanent voltage supply is made from

the vehicle battery to the ECM (not FirstGeneration models). This allows the self-diagnostic function to retain data of anintermittent nature. Once the ignition isswitched on, a voltage supply to the ignitioncoil and to the ECM is made from the ignitionswitch. This causes the ECM to earth the mainfuel injection relay. A relay-switched voltagesupply is thus made to the ECM from the mainfuel injection relay.

The majority of sensors (other than thosethat generate a voltage such the CAS, KS andOS), are now provided with a 5.D-voltreference supply from a relevant pin on theECM. When the engine is cranked or run, aspeed signal from the CAS causes the ECM toearth a pin so that the fuel pump will run.Ignition and injection functions ,are alsoactivated. All actuators (injectors, ISCVetc),are supplied with nbv from the main relay,andthe ECM completes the circuit by pulsing therelevant actuator wire to earth.

Self-diagnostic function(not First Generation)

The First Generation Motronic system doesnot have a self-test capability. All laterMotronic systemsare equippedwith a self- .

test capability that regularly examines thesignals from engine sensors, and internallylogs a code in the event of a fault beingpresent. This code can be extracted from theMotronic serial port (SO connector) by asuitable fault code reader.

Some systems utilise a warning lamp circuitso that when the ECM detects that a majorfault is present, it earths the warning lamp pinand the warning lamp on the dash will light.The lamp will stay lit until the fault is no longerpresent. If the fault clears, the code willremain logged until wiped clean with asuitable FCR, or when the battery isdisconnected. In Citroen and Peugeotapplications, a number of faults are designateas minor faults. These faults do not turn onthe warning lamp, although a fault code is stilllogged by the ECM. The failure of many of thesystem sensors are designated as minorfaults.

Limp-home facility (LOS)Motronic has a limp-home facility LOS). In

the event of a serious fault in one or more ofthe sensors, the EMS will substitute a fixeddefault value in place of the defective sensor.

This means that the engine may actually ru-quite well with failure of one or more minc'sensors. However, since the substitutecvalues are those of a hot engine, cold startirt!;and running during the warm-up period ma,be less than satisfactory. Also, failure of amajor sensor, ie the AFS, will tend to makedriving conditions less easy.

Adaptive systemsMotronic is adaptive to changing engine

operating characteristics, and constantl)monitors the data from the various sensors (ieAFS or MAP, ATS, CTS. TPS etc). As theengine or its components wear, the ECMreacts to new circumstances by adopting thechanged values as a correction to the basicmap.

Reference voltageVoltage supply from the ECM to many of

the engine sensors is at a 5.0 volt referencelevel. This ensures a stable working voltage,unaffected by variations in system voltage.

The earth return connection.for most enginesensors is made through an ECMpin that isnot directly connected to earth. The ECMinternally connects that pin to earth via one ofthe ECM pins that are directly connected toearth.

Signal shieldingTo reduce RFI, a number of sensors (ie

CAS, HES, KS, amplifier and OS) use ashielded cable. The shielded cable isconnected to the main ECM earth wire atterminal 19 to reduce interference to aminimum.

Vehicle speed sensor (VSS)The VSS is used to advise the ECM of

vehicle speed. It usually operates upon theHall-effect principle, and is mounted directlyupon the gearbox or on the back of thespeedometer drive.

A voltage is applied to the VSS from thesystem relay or ignition switch. As thespeedometer cable turns, the Hall switch isalternately turned on and off to return asquare wave signal to the ECM. Thefrequency of the signal is geared to so manypulses per revolution of the speedometercable, and is in direct proportion to the vehiclespeed.

3 Primarytrigger

CAS (not First Generation)The primary signal to initiate both ignition

and fuelling emanates from a CAS mounted inproximity to the flywheel. The CAS consists ofan inductive magnet that radiates a magneticfield: A number of steel teeth are set into theperiphery of the flywheel at equidistant

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Bosch Motronic MPi (35, 55 and BB-pin types) 6-5

6.2 TDC (B) and RPM (D) sensors(First Generation Motronic). Reversing themulti-plug connections to these sensors

will prevent the engine from starting

intervals. As the flywheel spins, and the teethare rotated in the magnetic field, an ACvoltage signal is delivered to the ECM toildicate speed of rotation. In addition, two ofthe teeth are omitted as a reference mark toTDC. As the flywheel spins, the two missingteeth cause a variance of the signal which isreturned to the ECM as reference to the TDCposition.

The peak-to-peak voltage of the speedsignal can vary from 5 volts at idle to over100 volts at 6000 rpm. In the ECM, ananalogue to digital converter (ADC)transforms:he AC pulse into a digital signal.

TDC and RPM sensors(First Generation only)

The primary signal to initiate both ignitionand fuelling emanates from two sensors"'!lounted in proximity to the flywheel. Thesensors are used to indicate the position of~C and the engine RPM (see illustration 6.2).

The TDC sensor consists of an inductive...,agnet that radiates a magnetic field. Areference mark to TDC (raised pin) is mounted~pon the flywheel- to indicate crankshaft:x>sitionas the flywheel spins.

The RPM sensor' also consists of an.,ductive magnet that radiates a magnetic~Id. A number of steel pins are set into theoeriphery of the flywheel at regular intervals.3.sthe flywheel spins, and the pins are rotated- the magnetic field, an AC voltage signal is::elivered to the ECM to indicate speed ofrotation.

The peak-to-peak voltage of the signals are=airlysimilar and can vary from 5 volts at idle::>over 100 volts at 6000 rpm. In the ECM, anarullogue to digital converter (ADC)transforms~e AC pulse into a digital signal.

4 Primaryandsecondary ignition

GeneralData on load (AFS or MAP), engine speed

:::;AS), engine temperature (CTS) and throttle:x)Sition (TPS or TS) are collected by the ECM,

H29293

6.3 External amplifier used in someMotronic systemsPin numbers shown

which then refers to a three-dimensionaldigital map stored within its microprocessor.This map contains an advance angle for eachoperating condition, and thus the best ignitionadvance angle for a particular operatingcondition can be determined.

AmplifierThe Motronic amplifier contains the circuitry

for switching the coil negative terminal at thecorrect moment to instigate ignition. Thesignal received by the amplifier from thetrigger is of an insufficient level to completethe necessary coil switching. The signal isthus amplified to a level capable of switchingthe coil negative terminal.

Mainly, the amplifier is contained within theECM, although some models utilise aseparate amplifier mounted on a heat sinkplate adjacent to the coil. The ECM thuscalculates the correct ignition dwell time andtiming advance from data received from itssensors, and sends a signal to the amplifierwhich then switches the coil negative terminal(see illustration 6.3).

Dwell operation in Motronic is based uponthe principle of the 'constant-energy current-limiting' system. This means that the dwellperiod remains constant at around 4.0 to5.0 ms, at virtually all engine running speeds.However, the dwell duty cycle, whenmeasured in percent or degrees, will vary asthe engine speed varies.

Ignition coilThe ignition coil utilises low primary

resistance in order to increase primary currentand primary energy. The amplifier limits theprimary current to around 8 amps, and thispermits a reserve of energy to maintain therequired spark burn time (duration) (seeillustration 6.4).

Ignition systemEither a distributor or an DIS is employed

for ignition pl,Jrposes. Refer to Chapter 2 formore details on the DIS.

DistributorWhere fitted, the distributor only contains

secondary HT components (distributor cap

and rotor), and serves to distribute the HTcurrent from the coil secondary terminal toeach spark plug in firing order. Ignition timingis not adjustable.

Knock sensor(some models only)

Many Motronic-equipped vehicles employ aknock sensor. The knock sensor is mountedon the engine block, and consists of apiezoceramic measuring element thatresponds to engine noise oscillations. Thissignal is converted to a voltage signal by theknock sensor, and returned to the ECM forevaluation and action.

The following description fits the knockcontrol processor (KCP) found on GM16-valve engines. Knock control in otherengines will function in a similar fashion. TheKCP analyses the noise from each individualcylinder, and sets a reference noise level forthat cylinder based upon the average of thelast 16 phases. If the noise level exceeds thereference level by a certain amount, knockcontrol identifies the presence of engineknock.

Initially, timing will occur at its optimalignition point. Once knock is identified, knockcontrol retards the ignition timing for thatcylinder or cylinders by a set number ofdegrees. Approximately 2 seconds afterknocking ceases (20 to 120 knock-freecombustion cycles), the timing is .advanced in0.750 increments until the reference timingvalue is achieved or knock occurs once more.This procedure continually occurs so that allcylinders will consistently run at their optimumtiming.

If a fault exists in the knock controlprocessor, knock control sensor or wiring, anappropriate code will be logged in the self-diagnostic unit, and the ignition timingretarded by 10.50by the LOS program.

Octane codingIt is not possible to adjust the ignition timing

on Motronic systems. However, in some

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H29294

6.4 Ignition coil used in Citroenand Peugeot DISsystems(eg Motronic 5.1 and 3.1)

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6.6 Bosch Motronic MPi (35, 55 and BB-pin types)

Vauxhall & Opel applications, an octanecoding plug is provided to enable the ECM toadopt different characteristics to suit variousoperating conditions.

5 Fuel injection (MPi)

I

GeneralThe Motronic ECM contains a fuel map with

an injector opening time for basic conditionsof speed and load. Information is thengathered from engine sensors such as theAFS or MAP sensor, CAS, CTS, and TPS orTS. As a result of this information, the ECMwill look up the correct injector pulse durationright across the engine rpm, load andtemperature range.

Fuel injectorsThe fuel injector is a magnetically-operated

solenoid valve that is actuated by the ECM.Voltage to the injectors is applied from themain relay,and the earth path is completed bythe ECM for a period of time (called pulseduration) of between 1.5 and 10 milliseconds.The pulse duration is very much dependentupon engine temperature, load, speed andoperating conditions. When the magneticsolenoid closes, a back-EMF voltage of up to60 volts is initiated.

Depending on model, there are severaldifferent methods of firing the injectors. Themethods are, simultaneous injection, bankedsimultaneous injection, and sequentialinjection.

Simultaneous injectionThe Motronic simultaneous injection

system is a Multi-point injection system, andpulses all injectors at the same time - iesimultaneously and twice per engine cycle.Half of the required fuel per engine cycle isinjected at each engine revolution. Duringengine start from cold, the pulse duration andnumber of pulses (frequency) are increased toprovide a richer air/fuel mixture.The fuel injectors are mounted in the inletstubs to the engine inlet valves, so that afinely-atomised fuel spray is directed onto theback of each valve. Since the injectors are allpulsed simultaneously, fuel will briefly restupon the back of a valve before being drawninto 8:cylinder.

Simultaneous injection (FirstGeneration)

The basic operation is similar to thesimultaneous injection described above.However, the injector is switched using twocircuits. Operation depends on the prim;:iplethat more current is required to open aninjector than to keep it open. This kind ofsystem is often termed 'current-controlledinjection' .

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Once the injector is open, a second circuitrapidly pulses the injector to earth. Theswitching is so rapid that the injector iseffectively held open, and less current isrequired during the operation. Advantages ofthis arrangement include a reduction ininjector operating temperature, andimmediate injector closure once the holdingcircuit is switched off.

Banked simultaneous injectionThe Motronic banked simultaneous

injection system is a Multi-point injectionsystem, and pulses all injectors at the sametime - ie simultaneously and once per enginerevolution. This means that half of the fuel forthe next power stroke is injected at eachopening of the injector and fuel lies briefly onthe back of an inlet valve until that valveopens. The injector thus opens twice for everyengine cycle. During engine start from cold,the pulse duration is increased to provide aricher air/fuel mixture. During engine cranking(hot or cold), the number of pulses (frequency)is increased from once per revolution to twiceper revolution. After 20 seconds of cranking,the pulse reverts to one pulse per revolution.

Although all four injectors are pulsedsimultaneously, the injectors are arranged intwo banks, with injectors 1 and 2 comprisingone bank, and injectors 3 and 4 making up theother bank. Each bank is connected to theECM via a separate ECM pin).

Sequential injectionThe Motronic sequential injection system is

a Multi-point system that pulses the injectorssequentially - ie in firing order and once perengine cycle. Each injector is connected tothe ECM via a separate ECM pin). Duringengine start from cold, the pulse duration andnumber of pulses (frequency) are increased toprovide a richer air/fuel mixture.

Cylinder identification(sequential injection only)

In earlier Motronic systems, the ECM doesnot recognise No 1 cylinder, or indeed eventhe firing order. This is because it is actuallyunnecessary. When the crankshaft ordistributor provides a timing signal, thecorrect cylinder is identified by themechanical position of the crankshaft,camshaft, valves and ignition rotor. Insystems where the injectors firesimultaneously, then the fuel will sit upon theback of an inlet valve until the valve opens.

Since fuel injection occurs on an individualcylinder basis in sequential systems, the ECMmust be informed which stroke a cylinder isactually on. On GM 16-valve engines, this isachieved by a cylinder identification sensorattached to the distributor, which works on theHall-effect principle. The sensor identifies No 1cylinder, and returns a signal to the ECM fromwhich the identification of all the other cylinderscan be calculated. The distributor is attachedto the exhaust camshaft (theengine is DOHC in

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6.5 Motronic distributor (GM, 2.5).The Hall-effect phase sensor (CID)multi-plug has been disconnected

configuration) (see illustration 6.5). Otherengines (eg BMW) utilise an inductive devicethat serves the same purpose but identifiesNo 1 cylinder by generatingan inductive pulse.

Load sensorsThe ECM requires a load sensor to detect

the flow of air into an engine. Once the volumeof air is known, the correct amount of fuel canbe looked up in the map. Several methods areused by the various Motronic systems tomeasure load. The vane-type AFS, the hot-wire air mass meter and the MAP sensor arethe three types most usually found.Vane-type AFS

The AFS is located between the air filterand the throttle body. As air flows through thesensor it deflects a vane (flap).The greater thevolume of air, the more will the flap bedeflected (see illustration 6.6).The vane isconnected to a wiper arm, which wipes apotentiometer resistance track and so variesthe resistance of the track. This allows avariable voltage signal to be returned to theECM.

Three wires are used by the circuitry of thissensor, and it is often referred to as a three-wire sensor. A 5-volt reference voltage isapplied to the resistance track, with the other.end connected to the AFS earth return. Thethird wire is connected to the wiper arm.

From the voltage returned, the ECM is ableto calculate the volume of air (load) enteringthe engine, and this is used to calculate themain fuel injection duration. To smooth out

AFS ASSEMBLY

6.6 Motronic type airflow sensor (AFS)

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Bosch Motronic MPi (35, 55 and BB-pintypes) 6.7

nlet pulses, a damper is connected to the Burn-offwillnot occur if.the engine speed hasAFSvane.TheAFSexerts a majorinfluence not exceeded 1000 rpm and the coolanton the amount of fuel injected. temperature is under approximately30°C.

Hot-wire or hot-filmair mass meter (AFS)

The hot-wire air mass meter has replacedthe vane-type AFS fitted to earlier vehicles.The hot-wire air mass meter measures themass of air entering engine, which allows anaccurate fuel injection pulse to be calculated.Hot-wire is a very accurate method ofcalculating the engine load (air input) andoften excludes the need for additional sensors

to measure air temperature and air pressure.Automatic compensation for altitude is thusprovided. The absence of moving partsimproves reliability and lessens maintenancerequirements (see illustration 6.7). .

Essentially, the hot-wire is so calledbecause a heated wire is placed in the airintake. As air passes over the wire, it has acooling effect in proportion to the mass of air.As air mass increases or decreases accordingto engine load, the ECM adjusts the currentflow to maintain the wire at its originalresistance and temperature. By measuring thechange in current flow, the ECM is able todetermine the mass of airflow into the engine.As the current" varies on the signal wire, sodoes the voltage, and an indication of loadcan be assessed bi measuring the variablevoltage signal. Voltage is applied to thesensor from the system relay. Operation of thehot-film AFS is very similar to hot-wire.

If a fault exists in the hot-wire AFS or wiring,an appropriate code will be logged in the self-diagnostic unit, and a substitute valueprovided by the LOS program.

Hot-wire burn-offOver a period of time, deposits tend to build

up upon the hot-wire, and this can lead tocontamination of the hot-wire. This is avoidedwith a 'burn-off' function, controlled by theECM during engine shutdown. Approximatelyfour seconds after the engine has beenswitched off, the ECM rapidly pulses the hot-wire terminal 4 of the AFS for 1.5 seconds.

6.7 Hot-wire or hot-film air mass meter (1)and ATS (2) in Motronic 1.5.2

MAPsensorA vacuum hose connects the MAP sensor

and the inlet manifold. Manifold vacuum actsupon the MAP sensor diaphragm, and theECM internally converts the pressure into anelectrical signal. MAP is calculated from theformula: Atmospheric Pressure less ManifoldPressure = Manifold Absolute Pressure.

Using the speed/density method, Motroniccalculates the AFR from the MAP signal andthe speed of the engine (CAS). This methodrelies on the theory that the engine will draw ina fixed volume of air per revolution.

When manifold vacuum is high (ie idlecondition), MAP is moderately low, and theECM provides less fuel. When manifoldvacuum is low (ie wide-open throttle), MAP ishigh and the ECM provides more fuel.

The inlet manifold on MPi models is a 'dry'manifold. Since fuel does not enter themanifold - due to injection being made ontothe.back of the inlet valve - there is no risk offuel being drawn into the MAP sensor tocontaminate the diaphragm, and a fuel trap isnot used.

The MAP sensor may be located internallyin the ECM (no connecting wires) or locatedinternally in the ECM. When locatedexternally, a 5-volt reference voltage issupplied to the sensor, with the other endconnected to earth. The third wire isconnected to a transducer which converts themanifold pressure signal into a voltage. As thepressure in the manifold varies, so too doesthe signal voltage returned to the ECM.

Air temperature sensor (ATS)The ATS is mounted in the AFS inlet tract,

and measures the air temperature before itenters AFS. Because the density of air variesin inverse proportion to the temperature, theATS signal allows more accurate assessmentof t~e volume of air being introduced to theengine.

The open-circuit supply to the sensor is at a5.0-volt reference level, and the earth path isthrough the AFS earth return. The ATSoperates on the NTC principle. A variablevoltage signal is returned to the ECM basedupon the air temperature. This signal isapproximately 2.0 to 3.0 volts at an ambienttemperature of 20°C, and reduces to about1.5 volt as the temperature rises to around40°C.

CO potentiometer ('pot')The CO pot mixture adjuster is lo~ated in

the AFS, and is a three-wire potentiometerthat allows small changes to be made to theidle CO. A 5.0-volt reference voltage isapplied to the sensor, and earth is via the AFSearth return circuit. The third wire is the COpot signal.

As the CO pot adjustment screw is turned,the change in resistance returns a voltagesignal to the ECM that will result in a changein CO. The CO pot adjustment only affectsidle CO. On catalyst-equipped models, theCO pot has no effect and the CO is thus non-adjustable.

CO adjustment(First Generation only)

The vane type of AFS fitted to early systemsutilises an air bleed screw located in the AFSto trim the CO value. An air channel allows asmall volume of air to by-pass the air flowingthrough the vane. As the by-pass is moved,the air volume acting upon the vane is altered,and the vane moves its position. The changedposition results in an altered signal to theECM and a change in fuel volume injected.

Coolant temperature sensor(CTS)

The CTS is immersed in the coolantsystem, and contains a variable resistancethat operates on the NTC principle. When theengine is cold, the resistance is quite high.Once the engine is started and begins to .warm-up, the coolant becomes hotter, andthis causes a change in the CTS resistance.As the CTS becomes hotter, the resistance ofthe CTS reduces (NTC principle) and Jhisreturns a variable voltage signal to the ECMbased upon the coolant temperature

The open-circuit supply to the sensor is at a [6t!5.0-volt reference level, and this voltage __JIreduces to a value that depends upon theresistance of the CTS resistance. The signal isapproximately 2.0 to 3.0 volts at an ambienttemperature of 20°C, and reduces to between0.5 to 1.0 volt at a normal operatingtemperature of 80 to 100°C. The ECM usesthe CTS signal as a main correction factorwhen calculating ignition timing and injectionduration.

Throttle potentiometer sensor(TPS)

A TPS is provided to inform the ECM of idleposition, deceleration, rate of accelerationand full-load (WOT) conditions. The TPS is apotentiometer with three wires. AS-voltreference voltage is supplied to a resistancetrack, with the other end connected to earth.The third wire is connected to an arm whichwipes along the resistance track, and sovaries the resistance and voltage of the signalreturned to the ECM.

From the voltage returned, the ECM is ableto calculate idle position (approximately0.6 volts), full-load (approximately 4.5 volts)and also how quickly the throttle is opened.During full-load operation, the ECM providesadditional enrichment. During closed throttleoperation above a certain rpm (deceleration),the ECM will cut off fuel injection. Injection willbe reintroduced once the rpm returns to idleor the throttle is opened.

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6-8 Bosch Motronic MPi (35, 55 and 88-pin types)

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Throttle switch (plternative to TPS)

A throttle swit0tJ; with dual contacts isprovided to inform1he ECMof idle position,deceleration, cruising and full-load (WOT)conditions. When the engine is at idle, the idlecontact is closed and the full-load contact isopen. As the throttle is moved to the fullyopen position, the full-loadcontact closes andthe idle contact becomes open. Undercruising conditions with a part-open throttle,both contacts are' open. During full-loadoperation, the ECM provides additionalenrichment. Duringclosed throttle operationabove a certain rpm (deceleration), the ECMwill cut off fuel injection. Injection will bereintroduced once the rpm returns to idle orthe throttle is opened.

Idle speed controlMotronic uses various methods to control

the idle speed during engine start-up, thewarm-up period and normal hot idle.

When an electrical load, such as headlightsor heater fan etc are switched on, the idlespeed would tend to drop. The ECM willsense the load and actuate the ISCVtoincrease the airflow through the valve andthus increase the idle speed. When the load isremoved, the ECMwillpulse the valve so thatthe airflow is reduced. Normal idle speedshould be maintained under all cold and hotoperating conditions. If the ISCVfails, it willfail-safe,with the aperture almost closed. Thiswillprovide a basic idle speed.ISCV (2-wire solenoid valve type)

The ISCVis a solenoid-controlled actuatorthat the ECM uses to automatically controlidle speed during normal idle and during'engine warm-up (see illustration 6.8). TheISCVis located in a hose that connects theinlet manifold to the air filter side of thethrottle plate. A voltage supply is applied tothe ISCVfrom the battery, and the earth forthe motor is made through a connection tothe ECM.

A duty cycle can be measured on the earthcircuit to determine the opening or closingtime period as a percentage of the total time

-available.

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6.8 Idle speed control valve (arrowed),seen from underneath vehicle -two-wire

Motronic 2.5 (GM)

6.9 Idle speed control valve, three-wire

ISCV(3-wire rotary type)The ISCV is a rotary actuator that the

Motronic ECM uses to automatically controlidle speed during normal idle and duringengine warm-up. The ISCV is located in ahose that connects the inlet manifold to the airfilter inside of the throttle plate.

The rotary ISCV.isa DC motor that the ECMcan rotate either clockwise or anti-clockwise.Rotating in one direction will open the valve;rotating in the opposite direction will cause itto close. A voltage supply is applied to theISGV from the battery, and the earth for themotor is made through two connections to theECM (see illustration 6.9).

Rotation of the motor in the appropriatedirection is accomplished by actuating themotor through one or the other of the earthcircuits. In reality, the two circuits areopposed. This prevents the valve from beingfully opened of closed in one particulardirection. The valve will thus take up anaverage position that reflects circuit bias to beopen or closed. Normally, this bias would betowards the open position.

A duty cycle can be measured on eachearth circuit to determine the opening orclosing time period as a percentage of thetotal time available.

Auxiliaryair valve(mainly First Generation)

The AAV is found in vehicles that do nothave any form of idle speed regulation. Anelectrically operated gate control valve is usedto increase the idle speed during cold engineoperation. The AAV is mounted in a hose thatby-passes the throttle plate. The valveresponds to temperature and allows extra airto by-pass the throttle when the engine iscold. Extra air entering the inlet manifoldcauses the idle speed to increase whichprevents low idle speed and stalling with acold or semi-cold engine.

During cold engine operation, the valve isopen and so engine idle speed is increased.As the engine warms-up, the valve graduallycloses until it is fully closed at normaloperating temperature.

The AAV resistance is connected to therelay output terminal. Once the engine hasbeen started voltage is applied to the AAV

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H29295

6.10 The multi-plug for the 15-pin relayPin numbers shown

resistance. The resistance is heated byvoltage ~nd the gate valve slowly closes sothat it is totally closed once the engine attain~normal operating temperature., Radiated heatfrom the engine will affect valve operation,and allow the valve to remain closed when theengine is hot and is not being operated.

Relays (typical operation)Depending on system, the Motronic

electrical system is controlled by either asingle system relay with dual contacts, or twoseparate relays (main system relay and fuelpump relay). Whatever, the general mode ofoperation is similar for all types. Although thefollowing method of operation is fairly typicalof a two relay operation, there are manyvariations on the theme. The relay terminalnumbers are those used in the European Dinspecification (see illustration 6.10).

A permanent voltage supply is made tomain relay terminals 30 and 86 and fuel pumprelay terminal 30 from the battery positiveterminal. When the ignition is switched on, theECM earths terminal 85 through an ECM pinwhich energises the first relay winding. Thiscauses the. main relay contacts to close, andthe supply through relay terminal 30 isconnected to the output circuit at terminal 87.A voltage supply is thus output at mainterminal 87. Terminal 87 supplies voltage tothe injectors, ECM, ISCVand the CFSV'(whenfitted). In addition, voltage is applied to thefuel pump relay contact terminal 86.

When the ignition is switched on. the ECMbriefly earths pump relay contact 85 at anECM pin. This energises the pump relaywinding, which closes the relay contact andconnects voltage from supply terminal 30 tooutput terminal 87, thereby providing voltageto the fuel pump circuit. After approximatelyone second, the ECM opens the circuit andthe pump stops. This brief running of the fuelpump allows pressure to build within the fuelpressure lines, and provides for an easierstart.

The pump relay circuit will then remainopen until the engine is cranked or run. Oncethe ECM receives a speed signal from -theCAS, the pump relay winding will again beenergised by the ECM, and the fuel pump willrun until the engine is stopped. Inaddition, the

Page 9: Bosch Mo Tronic

Bosch Motronic MPi (35, 55 and BB-pin types) 6-9

os heater circuits is usually wired to thepump circuit so that the OS heater will onlyoperate whilst the engine is running.

Fuel pressure syst~mThe fuel pressure systems in Motronic-

equipped vehicles all function in a similarfashion. The main difference concerns thelocation of the fuel pump which may bemounted externally, or internally in the fueltank. The types are described as follows.

External pumpThe roller type fuel pump, mounted close to

the fuel tank, draws fuel from the tank andpumps it to the fuel rail via a fuel filter.

Internal pumpThe fuel pump is mounted vertically in the

fuel tank, and is of the gerotor type. Fuel isdrawn. through the pump inlet, to bepressurised between the rotating gerotorteeth and discharged from the pump outletinto the fuel supply line.

Fuel transfer pumpIn some models, a secondary in-tank fuel

transfer pump aids the external pump. Theinternal fuel pump assembly operates on thegerotor principle .described above.

Fuel pump (all)The fuel pump normally provides much

more fuel than is required, and surplus fuel is

Adjustments

thus returned to the fuel tank via a return pipe.In fact, a maximum fuel pressure in excess of5 bar is usually possible. To prevent thepossibility of pressure loss in the supplysystem, a non-return valve is provided in thefuel pump outlet. When the ignition isswitched off, and the fuel pump ceasesoperation, pressure is thus maintained forsome time.

Fuel pressure regulatorFuel pressure in the fuel rail is maintained at

a constant 2.5 or 3.0 bar (depending uponvehicle) by a fuel pressure regulator. Thepressure regulator is fitted on the outlet sideof the fuel rail, and maintains an evenpressure of 2.5 or 3.0 bar in the fuel rail.

A vacuum hose connects the upperchamber to the inlet manifold, so thatvariations in inlet manifold pressure will notaffect the amount of fuel injected. This meansthat the pressure in the rail is always at aconstant pressure above the pressure in theinlet manifold. The quantity of injected fuelthus depends solely on injector opening time,as determined by the ECM, and not on avariable fuel pressure.

At idle speed with the vacuum pipedisconnected, or with the engine stopped andthe pump running, or at full-throttle, thesystem fuel pressure will be approximat~ly2.5 bar or 3.0 bar. At idle speed (vacuum pipe

connected), the fuel pressure will beapproximately 0.5 bar under the systempressure.

6 Catalyticconverter andemission control

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Catalytic converterVersions with a catalytic converter will also

be fitted with an oxygen sensor so thatclosed-loop control of emissions can beimplemented. The OS is heated so that it willreach optimum operatinQ temperature asquickly as possible after the engine is started.The OS heater supply is usually made fromthe fuel pump relay. This ensures that theheater will only operate whilst the engine isrunning.

Carbon filtersolenoid valve (CFSV)

An CFSV and activated carbon canister arealso be employed to aid evaporative emissioncontrol. The carbon canister stores fuelvapours until the CFSV is opened by the EMSunder certain operating conditions. Once theCFSV is actuated by the EMS, fuel vapoursare drawn into the inlet manifold to be burntby the engine during normal combustion.

.17 Adjustment pre-conditions

1 Ensure that all of these conditions are metbefore attempting to make adjustments

a) Engine at operating temperature. Engineoil at a minimum temperature of ao°c; ajourney of at least 4 miles isrecommended (particularly so if equippedwith AT).

b) Ancillary equipment (all engine loads andaccessories) switched off.

c) AT vehicles: Transmission in N or P.d) Engine mechanically sound.e) Engine breather hoses and breather

system in satisfactory condition.~ Induction system free from vacuum leaks.g) Ignition system in satisfactory condition.h) Air filter in satisfactory condition.i) Exhaust system free from leaks.j) Throttle cable correctly adjusted.k) No fault codes logged by the ECM.Q OS operating satisfactorily (catalyst

vehicles with closed-loop controlj.

2 In addition, before checking the idle speedand CO values, stabilise the ~ngine as follows:

a) StabilisM the engine. Raise the enginespeed to 3000 rpm for a minimum of

30 seconds, and then let the engine idle.

b) If the cooling fan operates duringadjustment, wait until it stops, re-stabilisethe engine and then restart theadjustment procedure.

c) Allow the CO and idle speed to settle.d) Make all checks and adjustments within

30 seconds. If this time is exceeded,

re-stabilise the engine and recheck.

8 Throttleadjustments

Throttle valve position1 Clean the throttle valve and surroundingareas with carburettor cleaner. Blow-by fromthe breather system often causes stickingproblems here (see illustration 6.11).2 The throttle valve is critical and should notnormally be disturbed. A common fault ismaladjustment of the idle speed by use of thethrottle stop screw.3 Where adjustment IS required:a) Disconnect the throttle cable, and remove

the tamperproof cap from the throttlestop screw.

b) Loosen the TPS or TSadjustment/retaining screws, rotate the

TPS or TS fully anti-clockwise andre-tighten the screws.

c) Unscrew the throttle stop screw untilthere is a gap between the stop andscrew.

d) Gently turn in the screw until it justtouches the stop.

e) Turn-in the screw one further half turnwhen there should be an air gap of

between 0.05 to 0.15 mm (0.002 tf) .f;;~0.006'?betweenthethrottlecasingand .~....

the throttle plate.~ Adjust the TPS or TS.g) Refit and readjust the throttle cable and' fit. Elnew tamperproof cap to the throttle.

stop screw.

H.2/205

6.11 Throttle valve adjustment

Page 10: Bosch Mo Tronic

6-10 Bosch Motronic MPi (35, 55 and BB-pin types)

Idle adjustment overview1 Refer to the test conditions described inSection 7.2 Checkthe that the throttle valve setting iscorrect as described above.3 Check the TS or TPS adjustment asdescribed above.4 Stabilise the engine. Raise the enginespeed to 3000 rpm for a minimum of 20seconds, and then allow the engine to idle.Make all checks and adjustments within 30

1 The ignition timing is not adjustable, and seconds. If this time is exceeded, re-stabilisemarks are not always provided. However, it is the engine and recheck. If the cooling fanuseful to make the following checks. If no operates duringadjustment, wait untilit stops,marks are available,make your own marks on re-stabilise the engine and then restart thethe front damper and pulley. adjustment procedure.2 Refer to the test conditions described in 5 Allowthe idle speed to settle, and checkSection 7. that the regulated idlespeed is correct.3 Allowthe engine to idle. 6 Ifthe idle speed is outside of the specified4 Connect a stroboscopic timinglight. parameters, check the system sensors for5 Record the approx!J;nate base ignition faults.timing.Note: The marks willfluctuate by a few. 7 Connect a gas analyser to the exhaustdegrees as the ECM varies the timiMJto ~.. system.

control the idle speed. f 8 Stabilise the engine as above.

6.12 Adjust the TS with the aid of anohmmeter. With the ohmmeter connected

between terminals 2 and 18 and thethrottle closed, the ohmmeter should

indicate zero (continuity)

I .

:11

Throttle switchConditions:enginestopped, throttleclosed,TS disconnected.4 Attach an ohmmeter between TSterminals2and 18. The ohmmeter should indicate zero(continuity)(see illustration 6.12).5 Open the throttle. The ohmmeter shouldindicate an open-circuit (infinity)(also seeillustration 6.13).6 As soon as the throttle moves off its stop.Anaudible 'click' should be heard.

ltdjust the TPSConditions: Engine stopped, throttle closed,ignition'on '.7 Attach a voltmeter between the signalterminal and earth and measure the voltage.8 The switch is requires adjustment if thevoltage is greater than 0.60.9 Loosen the two securing screws and adjustthe switch until the voltmeter indicates lessthan 0.60 volts.

9 Ignitiontimingchecks

-,-

6.13 With the ohmmeter connectedbetween terminals 3 and 18 and the

throttle fully open, the ohmmeter shouldindicate zero (continuity)

6 Increase the engine speed. The timingmarks should smoothly advance. Expectapproximately 25 to 35° of timing advance at3000 rpm.7 If the timing is not being controlled properlyby the ECM, suspect one of the followingfaults:

a) Theengine is in LOS, due to one or moreserious sensor failures.

b) TheECM is faulty.

10 Idleadjustments

'~.L

6.14 Adjustment of the idle CO pot locatedin the vane-type AFS

9 Allow the CO value to settle, and check theidle CO value.

CO adjustment(non-cat models only)Air bleed screw(First Generation Motronic)10 Where adjustment is necessary, removethe tamperproof plug covering the COadjustment screw in the AFS.11 Stabilise the engine as above.12 Turn the adjustment screw until the COstabilises at the specified figure). Turn thescrew clockwise to increase the CO level, anti-clockwise to decrease the CO level.13 If the CO level remains at a low level and'does not respond to adjustment, check for aninduction vacuum leak. The slightest leak willadversely affect the idle mixture.

CO pot in AFS (vane-type AFS)14 Slide back the rubber boot, and connect avoltmeter between the signal wire and earth.'A voltage of approximately 2 to 3 volts shouldbe obtained (see illustratiOn 6.14).15 If the voltage is outside of the statedparameters when the CO is correct, check thesystem for:a) Vacuumleak.b) Incorrect AFS or MAP signal.c) Incorrect CTS signal.d) Fouled or leaking injectors.e) Incorrect fuel pressure.

16 Stabilise the engine as above.17 Remove the tamperproof cap and turn theCO adjustment screw. Turn the screwclockwise to increase CO level and raisevoltage, anti-clockwise to reduce CO level andlower voltage.18 Refer to the CO pot test if the voltagedoes not vary or no voltage can be obtained.

.....

Page 11: Bosch Mo Tronic

Bosch Motronic MPi (35, 55 and BB-pin types) 6-11

System sensor and actuator tests

!mportant note: Please refer to Chapter 4, which describes common test procedures applicable to this system. The routines in Chapter 4 should:Jeread in conjunction with the component notes and wiring diagrams presented in this Chapter. The wiring diagrams and other data presented in;his Chapter are necessarily representative of the system depicted. Because of the variations in wiring and other data that often occurs, even:Jetween similar vehicles in any particular VM's range, the reader should take great care in identification of ECM pins, and satisfy himself that he185gathered the correct data before failing a particular component.

11 Crank angle sensor (CAS)

General1 Refer to the note at the start of this S~ction,

and refer to the relevant Section of Chapter 4.2 CAS resistance measurements (ohms):

a) BMW, Motronic First Generation:960 :I::96

b) BMW, Motronic 1.3, 1.7, 3.1:550 :I:: 50

c) Citroen/Peugeot, Motronic 4. 1:600 to 1600

d) Citroen/Peugeot, Motronic 1.3, 3.1, 3.2,5.1: 300 to 600

e) Opel and Vauxhall, Motronic 1.5, 2.5, 4.1:500 to 800

f) Volvo, Motronic First Generation:1000

12 Primary ignition

1 Refer to the note at the start of Section 11,

and refer to the relevant Section of Chapter 4.Many different combinations of primaryIgnition layouts may be found in Motronic

systems, and so select the test procedure for:he closest one to the system under test.2 ECM pin No 1 is connected to coil terminal 1;" all versions of Motronic with internal

amplifier that we checked.

3 ECM and amplifier terminals numbers mayvary depending upon Motronic system.4 The majority of Motronic systems utilise aCAS as the primary trigger.S For the ignition coil resistance specifications,-afer to the table below.

13 Knock sensor (KS)

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.

14 Fuel injector operation

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The ECM may pulse the injectors fully openor according to the current control principle(First Generation Motronic).3 Where injection is of the current-controlledkind, very few dwell meters may be capable ofregistering the rapid pulsing to earth thatoccurs during the second stage of the pulseduration. The meter may only register theswitch-on circuit of approximately 1.0 or2.0%. This means that the injector duty cyclereading will be inaccurate, and notrepresentative of the total pulse width seen inthe circuit.4 In some Motronic systems the frequency ofinjection increases for several seconds duringinitial cranking.

Injector resistance tests5 Remove each injector multi-plug andmeasure the resistance of the injectorbetween the two terminals.

a) First Generation Motronic: 4 ohms.b) All other Motronic systems: 16 ohms.

15 Hall-effect phase sensor(CID,GM 16-valve engines)

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The HES is located in the distributor.

BMW, Motronic First GenerationBMW, Motronic 1.3,1.7,3.1CitroenlPeugeot, Motronic 4.1CitroenlPeugeot, Motronic 1.3, 3.1, 3.2, 5.1 (Valeo)Opel and Vauxhall, Motronic 1.5, 2.5, 4.1Volvo, Motronic First Generation

CQilresistance measurements (ohms) -Section 12Primary0.60 to 1.000.30 to 0.800.800.60 to 0.800.60 to 0.760.45 to 0.55

,~Secondary8250,~5000 tb iooo65008600 to 95006400 to 110005400 to 6600

3 An average signal voltage of approximately2.5 volts or an approximate duty cycle of 50%should be obtained.

16 Airflowsensor (AFS)

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.The AFS may be of the vane, hot-wire or hot-film type, depending on system.

17 MAP sensor

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The MAP sensor may be a separate sensorlocated in the engine compartment, or mightbe located internally in the ECM depending onsystem.

--18 Air temperature sensor (ATS)

-- oJ1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The ATS may be located in the inlet tract ofthe AFS or in the inlet manifold, depending onsystem.

19 CO potentiometer ('pot')

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The CO pot will either be located in the

AFS, or might be a separate sensor located if!,thEt engir~ compartment, depending on<.

. system.

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.

I

I),

Page 12: Bosch Mo Tronic

6-12 Bosch Motronic MPi (35, 55 and BB-pintypes)

~~ Throttle switQh .(TS) 24 ECMvoltagesupplies and earths

26 Fuel pressure

1 Refer to the note at the start of Section 11, 1 Refer to the note at the start of Section 11, 1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4. and refer to the relevant Section of Chapter 4. and refer to the relevant Section of Chapter 4......

22 1"hrottlepotentiometer~e"'$Or (TPS)

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.--~i .

23 Idle speed control valve, (ISCV)~

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 ISCV resistances:

a) 2-wire ISCV: 8 to 10 ohmsb) 3-wire ISCV: 40 ohms from middle

terminal to either of the outer terminals,80 ohms between the two outer terminals.

25 System relays

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Chapter 4.2 The majority of Opel and Vauxhall vehiclesutilise a single 6-pin relay with dual contacts.Pin numbering is along the DIN lines.3 Many Citroen and Peugeot vehicles utilise asingle 15-pin relay with dual contacts. Num-bering is from one to 15 (seewiring diagram).4 Testing of multi- pin relays follows similarlines to that described in Chapter 4, and therelay supplies, earths and outputs should bechecked for voltage. The relay can be by-passed as before with a jumper wireconnecting the battery supply terminal to anappropriate output terminal.

27 Oxygen sensor (OS)

1 Refer to the note at the start of Section 11,and refer to the relevant Section of Ch'apter4.2 The OS found in the majority of Motronicsystems is a four-wire sensor.

28 Carbon filtersolenoid valve (CFSV)

1 Refer to the note at the start of Section 11,and refer to the relevant Section-of Chapter 4.

Pin table -typical 35-pin (First Generation Motronic, BMW)Note: Refer to illustrations 6.15 to 6.19

1 Coilnegative2 TS idle contact3 TS full-loadcontact4 Startermotor5 Earth6 AFS return7 AFS output8 RPMsensorsignal9 AFS supply10Earth(auto only)11Fuelconsumption gauge12 Simplified CO testing

13 CTS supply loutput14Injectors 1 to 3 (pulse)15Injectors4 to 6 (pulse)16Earth "

17Earth18 Battery19 Earth20 FPrelaydriver21 Tachometer22 ATS: (AFS)23 RPM sensor shield

24 OS signal

.It

25 TOC sensor return

26 TOC sensor signal27 Rpm sensor return28 AIC29 AIC30 -31 OS relay driver32 - ' .33 fSCV pulse34 ISCV pulse35 Supply from main relay'

. 0:<

_.". ,

1 18

\ ~ .

. " ..

(].c -,cccc~~=~~~c""cc~~c~,,;'c~ - ~~..19 35 EQH619 "

6.15 Typical 35-pin multi-plugPin numbers shown

Page 13: Bosch Mo Tronic

Bosch Motronic MPi (35,55 and SS-pin types) 6.13

Pin table - typical 35-pin (Motronic 3.1, Citroen/Peugeot)Note: Refer to illustrations 6.15 to 6.19

1 Ignition output to amplifier, coil ~>ne2 Ignition output to amplifier, coil two3 TPS signal contact4 Diagnostic socket5 Earth6 Sensor retum ATS, CTS, CO pot, TPS7 -8 -9 Sensor supply CO pot, TPS10 -11 -12 Diagnos"ocket

ECU EQH622

earth

igniOOnMoh: t15

6.16 Typical 35-pin ignition wiring diagram

. ECM

13

13 CTS supply /output14 Injectors (pulse)15 -16 Earth17 Diagnostic socket18 Battery supply19 -20 FP relay driver21 Tachometer

22 A TS supply/output23 CAS return

24 CO pot signal

25 CAS supply/signal26-27 Earth

28 PIN switch (AT only)29 A/C switch30-31-32 AlC compressor supply relay33 -34 -35 Nbv supply from main relay

5

fuel injectionrelay

33 35 16 19 20 18ignition switch

fuel pumprelay

injectors 5

EQte23 fuseearth

I

r=-iI~ -J1 2 . ISOI 1 Ifuel pump

11

,

.

~ '11

6.17 Typical 35-pin relays and components wiring diagram

ECM \EQH625

35

~

11

I3397622 2 314

Earth

2 11 11 13 12 14 152

1

181

3(1) (2) (3:.

fuelinjectionrelay: t87

1 2 1 2 1 11 2 1 2Injectors6.18 Typical 35-pin sensors

wiring diagram2 43

6.19 Typical 35-pin injectorswiring diagram

Page 14: Bosch Mo Tronic

6.14 Bosch Motronic MPi (35, 55 and BB-pin types)

Pin table - typical 55-pin (Motronic 1.5, Vauxhall)Note: Refer to illustrations 6.20 to 6.25

1 Coilnegative2 Earth3 Relayearth4 ISCV5 CFSV6 4 WDunit,AT control unit7 AFS signal9 Road speed sensor10 OS return12AFS supply12 TPS supply13 Diagnosticsocket14 Earth16 Injectorpulse, bank number 117 Injectorpulse, bank number 2

II

.........

18 Battery positive19 Earth (main ECM)20 Coding earth (non-cat)21 Coding earth (cat)22 Warning lamp24 Earth

25 Sensor return: AFS, ATS, CO26 Sensor retum: CTS, TPS, OA27 Ignition switch28 Oxygen sensor32 On board computer34 AT control unit

36 Relay earth37 Nbv supply from relay40 AC cut-off switch

EQH620 19

41 AC pressure switch42 Ignition switch42 Coding earth (MT)43 CO - non-cat (AFS)44 ATS (AFS)45 CTS supply/signal46 Octane adjuster47 Earth (4x4)48 CAS return49 CAS output51 AT control unit

53 Throttle pot signal55 Diagnostic socket

1

ccccccccccc~ccccc~cc~cccc~cc~~ccc~cccc~cccc~cc~~ccc~c

55

6.20 Typical 55-pin multi-plug

ECM 14 47 48 1924 'Z1

SCREEN

oFLYWHEEL

.. + 15

BATTERY. - IGNITIONSWITCH

QO

38

--

6.21 Typical 55-pin ignition wiring diagram

H29297

Page 15: Bosch Mo Tronic

1

Bosch Motronic MPi (35, 55 and 88-pin types) 6.15

ECM 14 24 27

18

battery

+1 30

r-f\ ignition15~ switch

5 19 28 10 37 36 3

fuel pumprelay

45

fuel injectionrelay

earth--~,

I3 3

injectors

IJ~..J.~WI

EQH627

fuel pump MV earth

6.22 Typical 55-pin relays and components wiring diagram

6.24 Typical 55-pin sensorswiring diagram

6.25 Typical 55-pin injectorswiring diagram

EARTH

ECM H29367

21 I I I 1 V I

AMPLIAER:t4 I.

L...J r-= ',1 "\.11:)4 l.MA1N CONTROLI

EARTH I I . I nl I I 1--rRELAY fer(FUEL INJECTION)

FU

r.

PUMPRELAY

1 ./

I'J

1

f;..

INJECTORS

DDD 0EARTH MV CFSV OXYGEN SENSOR FUEL PUMP

6.23 Typical 55-pin relay and components wiring diagram

liT ECM'I I

16ECM

45 30 43 12 7 26 44 52 53

2 11 h 13 12 14 15

tjtjtjISCV CFSV 1 INJECTORSAFS TS -

Page 16: Bosch Mo Tronic

6.1B Bosch Motronic MPi (35, 55 and BB-pin types)

Fault codes

29 Obtainil19 fault codes

BMWand Volvo1 All of the Motronic EMS's fitted to thesevehicles ranges require a dedicated FCR toaccess fault codes. Flash codes are not

av~ilable for output from any of thesesystems. For the sake of completeness, wehave provided fault code charts for BMWvehicles. At this time, code charts for theother vehicles are not available. Note: Flashcodes are available for a small number ofcodes on BMW vehicles marketed in the USA.These vehicles alone are equipped with adash-mounted warning lamp.

I.

I

Citroen and Peugeot2 If a FCR is available, it could be attached tothe SO serial connector and used for thefollowing purposes:a) Obtain fault codes.b) Clear fault codes.c) Obtain Datastream information.d) Actuate the system actuators: Thismay

include one or more of the actuators onthe following list:Fuel injectorsISCVCFSV (where fitted)

3 If a FCR is not available, it is still possible toobtain fault codes so long as the SO plug is ofthe two-pin type. A FCR is required for thosesystems equipped with the 16-pin SO plug.4 When the ECM determines that a fault ispresent, it internally logs a fault code, and willalso illuminate the diagnostic warning lamp ifthe fault is regarded by the system as major.Faults regarded as minor will not illuminatethe warning lamp, although a code will still belogged. All of the various two-digit fault codesin Citroen and Peugeot vehicles equippf'dwith a Motronic system are of the 'slow'variety, and can be output as flash codes onthe dash-mounted warning lamp. The firstseries of flashes indicates the number of tens,the second series of flashes indicates thesingle units (see illustration 6.28).Obtaining codes without a FCR

a) Attach an on loft accessory switchbetween the FCRgreen multi-plugterminal 2 (see Diagram) and earth.

b) Switch on the ignition.c) Close the switch for three seconds (the

dash warning lamp will remain off).

! I

11

I!IW:.

ACCESSORYSWITCH

l?lEARTH

6.28 Obtaining flash codes:Citroen and Peugeot

dJ Open tile sWIYcll, tile wamlng (amp Wlr(;-Flash once (indicating 10).Pause for 1.5 seconds.

Flash twice (indicating 2).This indicates the code of twelve (12)which is the test start code.

e) The waming lamp will extinguish.f) Close the switch for three seconds (the

dash warning lamp will remain off).g) Open the switch, the warning lamp will

flash to indicate a code.

h) Once the lamp has extinguished, wait forthree seconds before continuing.

ij Close the switch for three seconds &

repeat the test to obtain further codes.When code 11 is obtained, this indicatesEnd of Test.

j) After code 11 is obtained the completetest may be repeated.

k) If code 11 is the first code obtained aftercode 12, no faults are logged by theECM.

Clearing fault codes from the memoryof the ECM

a) Repair all circuits indicated by the faultcodes.

b) Switch on the ignition.c) Perform the test as detailed above to

reveal code 11 with no fault codes

(optiona/).d) Close the accessory switch for more than

ten seconds.

e) The warning lamp will remainextinguished.

Checking operation of the fuelinjectors and ISCV without a FCRa) Close the accessory switchb) Switchtheignitionon.c) Wait 3 seconds.

d) After a moment the fuel injectors willfunction. This can be determined byvibration and the sound of the injectorsclicking. Warning: Avoid the injection ofexcess fuel into the cylinders bycompleting the test quickly.

e) If the injectors fail to operate, refer to thefuel injector tests.

f) Continue with the next test to check theISCV.

g) Close the accessory switch for threeseconds once more.

h) After a moment the ISCV will function anavibrate to the touch.

i) If the ISCV fails to operate, refer to theISCV tests.

Opel and Vauxhallvehicles5 If a FCR is available, it could be attached tothe SO serial connector (the Vauxhall term fO"tne SO p(ug is ALOLJ and used for tnefollowing purposes:a) Obtain fault codes.b) Clear fault codes.c) Obtain Datastream information.d) Actuate the system actuators: Thismay

include one or more of the actuators on

the following list:Fuel injectorsISCVCFSV (where fitted)

6 If a FCR is not available, it is still possible toobtain fault codes so long as the SO plug is ofthe 10-pin type. A FCR is required for thosesystems equipped with the 16-pin SO plug.

Obtaining codes without a FCR7 Use a jumper lead to bridge terminals A anaB in the SO (ALOL)plug. The codes are theroutput on the instrument panel warning lamp.By counting the flashes and referring to thefault code table, faults can thus bedetermined (see illustration 6.29).

Ignitionsupply

EarthALDLmultiplug

Jumperlead

6.29 Obtaining flash codes:

GM (Opel & vauxht

Page 17: Bosch Mo Tronic

Bosch Motronic MPi (35, 55 and 88-pin types) 6-19

Fault code table - BMW Motronic 1.1, 1.3Flash codes (US)Note: US vehicles only: These codes are available via the flashing of the dash-mounted 'Check Engine' warning lamp. Other codes are onlyavailable when accessed by the Bosch KTS300 FCR or a BMW FCR.

Code Item1 AFS2 Oxygen sensor:3 CTS4 TS

Fault codesNote: These codes are only available when accessed by the Bosch KTS300 FCR or a BMW FCR.Note: Most of the fault code numbers co"espond to the ECM pin number. e.g. fault code 4 cOffesponds to ECM pin number 4.C~6 ~m ~~

1 ECM Clear the fault code memory and read the codes again, if the code persists, replace ECM3 Fuel pump relay Open-circuit or short to earth4 ISCV Open-circuit or short to earth5 CFSV Short to earth7 AFS AFS signal less than 0.04 volts or greater than 0.95 volts10 OS Exhaust emissions too rich or too lean15 Warning lamp (US only) Short to earth16 Injectors (cyl1 +3) Open-circuit or short to earth17 Injectors (cyl 2+4) Open-circuit or short to earth23 OS heater relay Short to earth, or short between ECM pin 23 and the OS relay28 OS Open-circuit or short to earth29 VSS No signal33 Solenoid valve kick down prevent Open-circuit or short to earth (AT models)37 ECM Supply exceeds 16 volts43 CO pot (non cat models) Open-circuit or short to earth44 ATS Open-circuit or short to earth45 CTS Open-circuit or short to earth51 Ignition timing intervention Short to earth (models with EGS only)52 TS Idle contact short to earth53 TS Full load contact short to earth54 Torque converter clutch Models with EGSonly: This code is stored when the ECM detects a closed torque

converter clutch or short to earth when the gear lever is in P or NLoose contactCheck the following: ECM supply voltages, CAS signal, AFS signals, fuel pump relayactivation, injection output signal, injector valves, fuel pressure test

100101

Output stage (Motronic 1.3 only)Engine operation not possible

Page 18: Bosch Mo Tronic

6-20 Bosch Motronic MPi (35, 55 and BB-pin types)

Fault code table - Citroen/Peugeot Motronic

Fault code table - BMW Motronic 1.7, 3.1

Code Item Fault Code Item Fault0 Undefined fault 50 Ignition amplifier cylinder No.41 Fuel pump relay/engine speed/CAS signal 51 Ignition amplifier cylinder No.62 Idle air control actuator 54 ECM Supply3 Injector Nos, 1 and 3 55 Ignition amplifier4 Injector No. 3 62 Electronic throttle control5 Injector No.2 64 Ignition timing (electronic AT) Interruption6 Injectors 67 Engine speed/crankshaft position sensor12 TPS 70 Oxygen sensor16 Camshaft position sensor 73 Vehicle speed sensor18 Amplifier to ECM terminal 18 Short-circuit 76 CO potentiometer (non-cat)19 ECM Defective signal 77 Intake air temperature sensor23 Ignition amplifier No.2 cylinder

78 Engine coolant temperature sensor24 Ignition amplifier No 3 cylinder25 Ignition amplifier No.1 cylinder 81 Alarm system signal26 ECM supply 82 Traction control Interrupted29 Idle air control actuator 83 Suspension control Interrupted31 Injector No.5 85 AC compressor32 Injector Nos. 2, 4, or 6 100 ECM Defective signal33 Injector No.4 200 ECM36 EVAPcanister purge valve 201 Oxygen sensor control37 Oxygen sensor Heating 202 ECM41 AFS Volume/mass 203 Ignition primary circuit46 ECM Defective signal 204 Electronic throttle control signal48 AC compressor Cut-out 300 Engine Cannot be started

Code Item Fault Code Item Fault11 End of diagnosis No faults present 51x OS Circuit fault (cat models only)12 Initiation of diagnosis 52 Mixture control Supply voltage/air/exhaust leak13x ATS 53x Battery voltage Chargingibattery tests14x CTS

'" 54 ECM ECM/ECM supply/injection relay15 Fuel pump relay Supply fault

".

55 CO pot Circuit fault21x TPS/TS Idle contact 56 Immobiliser system22 ISCV Supply fault 65 CID25 ACAV 71 No 1 injector control31 Idle switch fault Motronic 5.1.1 72 No 2 injector control31 OS Mixture regulation (check OS signal 73 No 3 injector control

voltage) (Motronic 3.1, 3.2) 74 No 4 injector control31 Mixture regulation Exhaust/inlet leak(s)or fuel

'x' Faults that typically will cause the ECM to enter LOS, and use a(cat models only) pressure/type (Motronic 1.3)32 Mixture regulation Exhaust/inlet leak(s)or fuel default value in place of the sensor

(cat models only) pressure/type Some faults are designated as major faults, and will illuminate the33 CFSV Circuit fault (Motronic 5.1.1) warning lamp. However, major faults that will illuminate the warning33x AFSIMAP Circuit fault (Motronic 4.1, 3.2) lamp vary from system to system, and it is best to interrogate the ECM34 CFSVfor codes if a fault is suspected.35 TS Full-load contactActuator selection code41 CAS

42 Injectors 82 Injector43x KS (Knock regulation) Knock sensor/engine temp/plugs etc 83 ISCV44x KS (Knock detection) Knock sensor 84 CFSV

Page 19: Bosch Mo Tronic

--------,

BoschMotronicMPi(35,55 andBB-pintypes) 6-21

Fault code table - GM MotronicCode Item Fault Code Item Fault

12 Initiation of diagnosis 65 CO potentiometer Low voltage13 Oxygen sensor No change in voltage/open- 66 CO potentiometer High voltage

circuit 67 TS - idle contact Idle switch not opening14 CTS Low voltage 69 ATS Low voltage

15 CTS High voltage 71 ATS High voltage16 Knock sensor No change in voltage 72 TS - full load contact Full load switch not opening

17 Knock sensor two No change in voltage 73 AFS Low voltage

18 Knock control unit No signal: ECM fault 74 AFS High voltage19 RPM signal Interrupted signal

75 Transmission switch Low voltage

21 Throttle pot High voltage 76 AT torque control Engaged long

22 Throttle pot Low voltage 79 Traction control unit Incorrect ignition/injector

23 Knock control modulecut-off

24 Vehicle speed sensor81 Injector number one Low voltage

25 Injector number one High voltage82 Injector number two Low voltage

26 Injector number two High voltage83 Injector number three Low voltage

27 Injector number three High voltage84 Injector number four Low voltage

28 Injector number four High voltage85 Injector number five Low voltage

29 Injector number five High voltage86 Injector number six Low voltage

31 Engine RPM signal No signal87 AC cut-off relay Low voltage

32 Injector number six Voltage high88 AC cut-off relay High voltage

33 Inlet manifold pressure sensor Voltage too high89 Oxygen sensor Low voltage

34 EGRvalve Voltage high91 Oxygen sensor High voltage93 HES Low voltage

35 ISCV Poor or no idle speed control 94 HES High voltage37 Engine self-diagnosis Low voltage 95 Hot start valve Low voltage38 Oxygen sensor Voltage low (1990 model 96 Hot start valve High voltage

year on) 97 Traction control unit Incorrect signal39 Oxygen sensor Voltage high (1990 model 98 Oxygen sensor Wiring break

year on) 99 Code unknown41 Vehicle speed sensor Low voltage 113 Turbo boost control Boost pressure high42 Vehicle speed sensor High voltage 114 Idle boost pressure Above upper limit 644 Oxygen sensor Air/fuel mixture too lean 115 Full boost pressure Below lower limit !..

45 Oxygen sensor Air/fuel mixture too rich 116 Boost pressure Above upper limit47 Air pump relay Low voltage 117 Wastegate valve Low voltage48 Battery voltage Low voltage 118 Wastegate valve High voltage49 Battery voltage High voltage 121 Oxygen sensor 2 Lean exhaust51 Programmable memory PROM error 122 Oxygen sensor 2 Rich exhaust52 Engine check light: final stage High voltage 123 Inlet manifold valve 1 Blocked

53 Fuel pump relay Low voltage 124 Inlet manifold valve 2 Blocked

54 Fuel pump relay High voltage 132 EGR valve Incorrect signal55 ECM fault Renew ECM 133 Inlet manifold valve 2 High voltage56 ISCV Short to earth 133 Inlet manifold valve 2 Low voltage57 ISCV Interruption 134 EGR valve 2 Low voltage

59 Inlet manifold valve Low voltage 134 Inlet manifold valve 2 High voltage61 FTVV Low voltage 135 'CHECK ENGINE' lamp Low voltage62 FTVV High voltage 136 ECM

63 Inlet manifold valve High voltage 137 ECM box High temperature

Page 20: Bosch Mo Tronic

ImprintPublished by:@ Robert Bosch GmbH, 1986Postfach 50, D-7000 Stuttgart 1.Automotive Equipment Product Group,Department for Technical Information(KH/VDT). '

Edltor-in-Chief: .

Dipl.-Ing. (FH) U. AdlerEditors:Dipl.-Ing (FH) H. Bauer,Dipl.-Ing. W. Bazlen t,F. Dinkler, Marion Her:werthProduction management: '

G., BergerLayout: .Dipl.-Ing. (FH) U. AdlerG~'BergerTranslation:Editor-in-Chief:P. GirlingEditor: .J.-F. Salas

Translated by:IngenieurbGrQ fUr Technische und-Naturwissenschaftliche UbersetzungenDr. W.-D. Haehl GmbH, Stuttgart,Edward L. Crosby IIITechnical graphics:Bauer & Partner GmbH, StuttgartJoint production:W. Wirtz Druck & Verlag, Speyer2nd corrected Edition based on the20th German Edition.

The worldwide selling rights and theright to issue foreign-language licensesfor the original German Edition (20thEdition, 1987) are held by:VDI-Verlag, GmbHVerlag des Vereins DeutscherIngenieure, Graf-Recke~Str. 85,D-4000 DGsseldorf 1,ISBN 3-18-418Q06-9

Approved Editions under license:SAE Society of .Automotive Engineers Inc.ISBN 0-89 283;p18-6Delta Press LimitedISBN 1 85 226 O~L9,

-_J~

Foreword to the 2nd Edition

1

Reproduction, duplication and transla-tion of this publication, including.excerpts therefrom, is only to ensuewith our previous written consent andwith particulars of source. Illustrations,descriptions, 'Schematic diagrams andother data ser~ only for explanatorypurposes and for presentation of thetext. They cannot be used as the basisfor design, installation and ,scope ofdelivery. We undertake no liability forconformity of the contents with nationalor local regulations.We reserve the right to make changes.

The brand names -given in the contentsserve only as examples and do notrepresent the classification or prefer-ence for a particular manufacturer.Trade marks are not identified as such.

The following companies provided illus-tratons and informative material: .

Audi AG, Ingolstadt;Bayerische Motorenwerke AG, Munich;Mercedes-Benz AG. Stuttgart;J. Eberspacher. Esslingen;Fichtel u. Sachs AG, Schweinfurt;Kienzle A~paratus GmbH, VS-Villingen;Sekurit-Glas Union GmbH, Aachen; .Voith GmbH, Heidenheim;Zahnradfabrik Friedrichshafen AG.Friedrichshafen.

The "Automotive Handbook" is ahandy, concise, pocket-sized referencework. Its primary purpose is to providethe automotive engineer, the mechanic,the student and all those interested intechnical 'matters, with a wealth of re-liable technical data.. as well as aninsight into the present-day state-of-artin automotive technology in the FederalRepublic of Germany. With this assign-

. ment in mind, the scope of the theoreti-cal chapters dealing with passengercars and commercial vehicles, as wellas the remaining contents, has beenkept to the practical and necessarylevel.

Within the framework of a pocketbook, it is impossible. to present adetailed coverage of individual techni-cal subjects. On the other hand, withthe very wide range of users in mind,'We did not want to dispense with gen-erally applicable topics and data.

This 2nd English Edition was revisedand up-dated by specialists f~om theBosch Group. For certain chapters,other firms also made contributions. Atthis point, we would like to express ourappreciation to all concerned.

The Editors

Printed in the .Federal Republic of Germany,.Imprime en Republique Fedeli8le "d'Allemag.ne. . ,

Editorial closing: 25. ~. 1987

.;

For your information:

Compared to the 1st Edition, we haveshortened the following subjects:Tables for trigonometric functions.Physics (meteorology, nuclear

physics).Ignition (magneto ignition, spark-plug

matching) .Diesel fuel-injection pumps

(single-plunger pumps).Motor traffic and motor-traffic

economics.Various: nationality plates,

racing classes. speeds,historical events.

We have extended:Format (pocket-book format)

and contents.Electrical engineering and electronicsMaterials (materials tables,

plastics abbreviations/tradenames, lubricants).

Internal-combustion (le) engines.Fuel metering

(electronically controlled car!:>uretor,KE-/LH-Jetronic, single-point 'injection, LPG installations).

Electronic governors(for diesel fuel-injection pumps)

Battery ignition (electronic ignition).Exhaust-gas techniques,Drive trains,

Undercarriage designs,Braking equipment,Lighting,Vehicle hydraulics/pneumatics.

We have Introduced:Control engineering,Data processing (microcomputers),Sliding bearings and rolling bearings,Threaded fasteners, Belt drives,Driving dynamics (commercial vehs),Hydrostatic drives, Hybrid drives,Superchargers for IC engines,Motronic,Vehicle bodies, passenger cars &

commercial vehicles,Vehicle glass windows, window and

lamp'cleaning,Electromagnetic compatibility (EMC),Trip recorders, Trip computers.Electromechanical drives,Passenger restraint systems.