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September 28, 2002 Page 1
Haga clic para modificar el estilo de subttulo del patrn
An Introduction to Vehicle Networks, Scan Tools, and
MultiplexingPresented by: Paul Baltusis
Powertrain Control System Engineering Diagnostic Systems
Department OBD-II Technical Specialist Revised: September 28,
2002
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In-Vehicle Networks
In-vehicle networking, also known as multiplexing, is a method
for transferring data between electronic modules via a serial data
bus.
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Benefits of Networking Eliminates redundant sensors and
dedicated
wires for each function (lower cost, lower weight, better
reliability)
Reduces number of wires and connectors (lower cost, lower
weight, better reliability, easier-to-package wiring harness)
Allows more features and more flexibility (modules share data,
more flexible design and vehicle option content)
Allows adding features via software upgrades
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Benefits of Networking
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Networking Methods
Class A Generic UART (Universal Asynchronous
Receiver/Transmitter) or other custom low speed device < 10
Kbps.
Class B Medium speed, for example J1850, between 10 Kbps and 125
Kbps (Ford DCL and SCP, GM Class 2)
Class C High Speed, for example CAN 2.0, between 125 Kbps and
1,000 Kbps (Controller Area Network)
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OBD Communication Protocols
OBD-II and EOBD regulations define the communication protocols
that can be used for diagnostics.
The intent was to reduce the proliferation of
manufacturer-specific protocols used for diagnostics.
This would lead to more generic, less expensive scan tools.
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OBD Communication Protocols
ISO 9141-2 (K-Line) ISO 14230-4 (Keyword Protocol 2000) J1850
41.6 Kbps Pulse Width Modulated J1850 10.4 Kbps Variable Pulse
Width J2284/ISO 15765-4 (CAN)
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OBD Communication Protocols
Only one OBD-compliant link may be brought out to the J1962 Data
Link Connector
OBD-II allows only 500 kbps CAN, EOBD allows 250 and 500
kbps.
CARB will force all manufacturers to use CAN for the 2008 MY
J2534 (pass through reprogramming) must use a generic OBD
link.
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Controller Area Network
CAN is a network protocol used to interconnect a network of
electronic control modules or nodes.Typically, a two wire, twisted
pair cable is used.CAN has a stringent set of rules, implemented in
the CAN chip, that supports the serial transfer of information
between two or more nodes.
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CAN Network
Where does CAN fit in the range of networks?
Networks are usually based on size:WAN Wide Area Network
(Internet)
LAN Local Area Network (Ethernet)
SAN Small Area Network (CAN)
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CAN CARB allows the use of CAN for 2003 MY and
beyond vehicles. EOBD allows the use of CAN for 2001 CY and
beyond vehicles. Some US manufacturers are planning to start
using CAN starting on some vehicles in the 2003 MY.
CARB requires the use of CAN on all vehicles for the 2008 MY and
beyond.
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CAN CAN messages have a specified structure that
is specified in CAN standards. CAN networks have rules (bitwise
arbitration)
for dealing with colliding messages when two modules start
transmitting messages at the same time.
There are two formats for addressing 11 bit and 29 bit
identifiers. 11-bit has a 2032 message limit, 29-bit allows for
millions of distinct messages.
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CAN Basic Message Structure
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CAN Message Arbitration
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J1850 41.6 PWM J1850 41.6 PWM is used by Ford. Ford
internally calls this protocol Standard Corporate Protocol
(SCP)
SCP is a true network protocol that incorporates bus
arbitration.
SCP is used for both vehicle network communication and
diagnostic communication.
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J1850 10.4 VPW
J1850 10.4 VPW is used by General Motors. GM internally calls
this protocol Class 2.
Class 2 is a true network protocol that incorporates bus
arbitration.
Class 2 is used for both vehicle network communication and
diagnostic communication.
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ISO 9141
ISO 9141 is used by many Japanese manufacturers.
ISO 9141 is not a network protocol, it can only be used for
diagnostics.
There is no bus arbitration. It can be used to connect one
diagnostic tool to a vehicle control module.
ISO 9141 is relatively slow 10.4 Kbps
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KWP 2000 KWP is used by many European
manufacturers. It uses an enhanced set of diagnostic messages
but retains the ISO 9141 physical layer.
KWP is not a network protocol, it can only be used for
diagnostics.
There is no bus arbitration. It can be used to connect one
diagnostic tool to one or more vehicle control modules.
KWP is relatively slow 10.4 Kbps
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Types of Network Messages There are two types of network
messages
Diagnostic messages Normal Mode messages
Normal Mode messages are used to share information between
modules on the network during normal vehicle operation, e.g.
instrument cluster sends fuel level info (percent fill) to PCM.
Normal mode messages always use physical addressing.
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Types of Network Messages Diagnostic Mode messages are used
to
communicate between a test tool and a module on the network.
Diagnostic messages can use either physical addressing or
functional addressing.
Manufacturer-specific tools normally use physical addressing
Generic OBD tools use functional addressing because the
configuration of the network and network addresses do not have to
be known for every specific vehicle
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SAE/ISO Diagnostic Specifications Vehicle diagnostic
communication
specifications have been written by the Society of Automotive
Engineers (SAE) and by various International Standards Organization
(ISO) workgroups.
These standards are referenced by the California, Federal and
European OBD regulations.
US regulations reference SAE standards, European regulations
reference equivalent ISO standards.
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SAE/ISO Diagnostic SpecificationsLegislated diagnostics SAE
J1930/ISO 15031-2 Electrical/Electronic Systems
Diagnostic Terms, Definitions, Abbreviations and Acronyms SAE
J1962/ISO 15031-3 Diagnostic Connector SAE J1978/ISO 15031-4 OBD-II
Scan Tool SAE J1979/ISO 15031-5 E/E Diagnostic Test Modes SAE
J2012/ISO 15031-6 Diagnostic Trouble Codes SAE J2186/ISO 15031-7
E/E Data Link SecurityNon legislated diagnostics SAE J2190/ISO
14229 Enhanced E/E Diagnostic
Test Modes
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SAE/ISO Multiplex SpecificationsLegislated multiplex standards
SAE J1850 (Class B Data Comm. Network
Interface) ISO 9141-2 (K-Line) ISO 14230-4 (Keyword Protocol
2000) SAE J2284/ISO 15765-4 (CAN) J2534 Recommended Practice for
Pass-Thru
Vehicle Programming
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SAE J1930 Terms and Acronyms J1930 attempts to limit the
proliferation of
terms, abbreviations and acronyms used in motor vehicle service
literature.
Examples Ford uses ECT (engine coolant temp sensor), GM
uses CTS (coolant temp sensor), J1930 uses ECT Ford uses ISC
(idle speed control), J1930 uses IAC
(idle air control) Ford uses EEC-V, J1930 uses PCM
(powertrain
control module)
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SAE J1930 Terms and Acronyms J1930 describes a consistent
methodology for
naming components and systems.
MODIFIERS BASE WORDWhat is Where Which What does What
Purpose? Is it?Temp? it sense? Is it?
Sensor (most generic)
Temperature Sensor
Coolant Temperature Sensor
Engine Coolant Temperature Sensor
Instrumentation Engine Coolant Temperature Sensor (most
specific)
Least > Most
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SAE J1962 Data Link Connector
J1962 describes the functional requirements for the vehicle and
test tool data link connector (DLC): In-vehicle location/access
Connector design Terminal assignments Electrical interface
requirements
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SAE J1962 Data Link Connector The 16-pin DLC assignments are
specified in
SAE J1962/ISO 15031-3Pin 1 - Discretionary Pin 9
Discretionary
Pin 2 Bus + J1850 Pin 10 Bus J1850
Pin 3 Discretionary Pin 11 Discretionary
Pin 4 Chassis Ground Pin 12 Discretionary
Pin 5 Signal Ground Pin 13 - Discretionary
Pin 6 CAN High Pin 14 CAN Low
Pin 7 K-Line ISO9141/KWP Pin 15 L-Line ISO9141/KWP
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SAE J1962 Data Link Connector The general location of the DLC is
specified in
J1962, however, CARB and EPA regulations are more
restrictive.
CARB specifies that DLC must be on drivers side of vehicle
centerline, not on center console, or behind storage
accessories.
A covered DLC must have label (e.g. OBD) approved by CARB.
Pin 16 must have < 20 Volts (not 24 or 42 V)
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SAE J1978 Generic Scan Tool J1978 defines the minimum
functionality
required by an OBD-II Scan Tool Automatic hands-off
determination of the
communication interface Displays status and results of on-board
diagnostic
evaluations Displays pending and confirmed DTCs Displays current
data, freeze frame data, and
vehicle information Clears DTCs, test results and freeze frame
Provides a user manual/help facility
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SAE J2012 Diagnostic Trouble Codes J2012 defines a set of
diagnostic trouble
codes (DTCs) where industry uniformity has been achieved.
DTCs consist of an alpha character followed by four characters
Pxxxx is reserved for powertrain DTCs Bxxxx is reserved for body
DTCs Cxxxx is reserved for chassis DTCs Uxxxx is reserved for
network DTCs
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SAE J2012 Diagnostic Trouble Codes The second character
designates whether the
DTCs and a generic SAE DTC or a manufacturer-specific DTC.
P0xxx, P2xxx, P3400, and U0xxx are generic DTCs
P1xxx, P30xx, P3100, P32xx and P33xx are manufacturer-specific
DTCs
The remaining characters designate the system associated with
the fault. The characters are hex and can range from 0 F.
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SAE J2012 Diagnostic Trouble Codes The J2012 committee defines
new DTCs on a
quarterly basis, based on manufacturer requests.
The J2012 committee assigns DTCs in a uniform manner using J1930
terminology.
Sample output:P2632 Fuel Pump B Control Circuit / Open
P2633 Fuel Pump B Control Circuit Low
P2634 Fuel Pump B Control Circuit High
P2636 Fuel Pump B Low Flow/Performance
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SAE J2012 Diagnostic Trouble Codes Sample input:P0A00 Motor
Electronics Coolant Temp Sensor Circuit
P0A01 Motor Electr. Coolant Temp Sensor Circuit Range /
Performance
P0A02 Motor Electr. Coolant Temp Sensor Circuit Low
P0A03 Motor Electr. Coolant Temp Sensor Circuit High
P0A04 Motor Electr. Coolant Temp Sensor Circuit Intermittent /
Erratic
Sample network DTCs:U0001 High Speed CAN Communication Bus
U0101 Lost Communication with TCM
U0302 Software Incompatibility with TCM
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SAE J2186 Data Link Security J2186 defines a method to access
secured
vehicle controller functions. Three parameters control security
access
the seed (sent by controller) and key (sent by external
device)
the delay time (minimum delay time between attempts)
the number of false access attempts
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SAE J1979 Diagnostic Test Modes
SAE J1979/ISO 15031-5 defines standard diagnostic test
modes.
Diagnostic/emission critical control modules must implement
these diagnostic test modes. They must be on the OBD data link or
must use another module as a gateway.
CARB defines engine and transmission control modules as
emission-critical.
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SAE J1979 Diagnostic Test Modes
Any other control module that performs a major OBD-II monitor or
performs CCM monitoring for more than two components is considered
to be diagnostic critical.
If a diagnostic/emission critical control module is
reprogrammable, it must respond with Mode $09 CALID and CVN.
It must be able to be reprogrammed using a SAE J2534
interface.
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SAE J1979 Diagnostic Test Modes J1979 specifies a set of
standard messages
that can be used by scan tool to obtain OBD-II data from a
vehicle. (Modes $01 to $09)
Functional addressing is used instead of physical addressing for
all messages because the test tool does not know which systems on
the vehicle have the OBD information that is requested.
Response times to messages are specified. Message lengths are
specified.
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SAE J1979 Diagnostic Test Modes Messages must utilize a standard
set of
header bytes specified for each communication protocol.
The remainder of the message (the data bytes) specify the type
of message (test mode) and specific data that is being
requested.
Header byte definitions are specified on the next two
slides.
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SAE J1979 Header Bytes
H e a d e r b y t e s C A N f r a m e d a t a f i e l d
CAN Identifier (11 or 29 bit) #1 PCI Byte
#2 #3 #4 #5 #6 #7 #8
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SAE J1979 CAN Header Bytes
C A N i d e n t i f i e r ( h e x )
D e s c r i p t i o n ( 1 1 - b i t a d d r e s s i n g )
7 D F C A N i d e n t i f i e r f o r f u n c t i o n a l l y a
d d r e s s e d r e q u e s t m e s s a g e s s e n t b y t h e e x
t e r n a l t e s t e q u i p m e n t .
7 E 0 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 1
7 E 8 P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 1 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 1 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 2
7 E 9 P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 2 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 2 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 3
7 E A P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 3 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 3 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 4
7 E B P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 4 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 4 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 5
7 E C P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 5 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 5 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 6
7 E D P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 6 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 6 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 7
7 E E P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 7 t o t h e e x t e r n a l t e s t e q u i p m e n
t
7 E 7 P h y s i c a l r e q u e s t C A N i d e n t i f i e r f
r o m t h e e x t e r n a l t e s t e q u i p m e n t t o E C U # 8
7 E F P h y s i c a l r e s p o n s e C A N i d e n t i f i e r f r
o m E C U # 8 t o t h e e x t e r n a l t e s t e q u i p m e n
t
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Ford Module Addresses
Module Phys Adr Func Adr Rec Adr Xmit Adr Func Rec Adr Func Xmit
Adr(J1850) (J1850) (CAN) (CAN) (CAN) (CAN)
PCM$10 $6A $7E0 $7E8 $7DF $7E8(Powertrain Control Module)TCM$18
$6A $7E1 $7E9 $7DF $7E9(Transmission Control Module)
ABS $28 $6A $7E2 $7EA $7DF non-OBD(Anti-lock Brake System)
AHCM $0F $6A $7E3 $7EB $7DF non-OBD(Auxiliary Heater Control
Module)
TCCM $18 $6A $7E4 $7EC $7DF non-OBD (Transfer Case Control
Module)
AFCM $16 $6A $7E5 $7ED $7DF $7ED(Alternative Fuel Control
Module)
SPCM $11 $6A $7E6 $7EE $7DF $7EE
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Mode $01 Retrieve Diagnostic Data
Mode $01 provides diagnostic data, commonly called PIDs
(Parameter ID)
Service technicians can use the data to troubleshoot sensors,
check OBD monitor completion, MIL status, etc.
Test tool specifies the requested data by PID number ($00
through $FF)
PIDs are defined in J1979 (number, units, conversion/scaling
factor, acronym)
PIDs must show raw values not substituted values if a sensor
fails
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Mode $01 Retrieve Diagnostic Data
The message format used to make a PID request is as follows:
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PID $01 I/M Readiness
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PID $02 and $03
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PIDs $04 - $11
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PIDs $12 - $1B
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PIDs $1C - $1E
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PIDs $1F - $2B
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PIDs $2C - $33
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PIDs $34 - $3F
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PID $41
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PIDs $42 - $4E
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Mode $02 Freeze Frame
Mode $02 stores Mode $01 PID data at the time a pending or
confirmed DTC is stored.
Fuel system and misfire DTCs have a higher priority and
overwrite any existing data.
Service technicians can use the data to understand the
conditions at the time the malfunction occurred.
Only one frame ($00) is required to be stored.
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Mode $02 Freeze Frame
Freeze frame can be useful, however, there are some caveats.
Freeze frame is stored when the DTC is stored, not when the
problem began.
For circuit faults, it usually takes 5 seconds to store a
DTC.
Misfire is evaluated every 1,000 revs. A misfire DTC may be
stored 60-90 seconds after the misfire initially occurred, at
substantially different rpm and load conditions.
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Mode $02 Freeze Frame
The message format used to retrieve freeze frame is as
follows:
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Mode $03 Retrieve emission-related DTCs
Mode $03 reports confirmed, emission-related DTCs.
Service technicians and I/M test stations use this mode to
determine what malfunction turned on the MIL.
Mode $03 reports history codes for 40 warm-ups after the MIL is
extinguished.
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Mode $03 Retrieve emission-related DTCs
The message format used to retrieve emission-related DTCs is as
follows:
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Mode $04 Clear DTCs and Diagnostic Information
Mode $04 clears/erases DTCs and resets diagnostic data at the
time a pending or confirmed DTC was stored. Diagnostic data
includes freeze frame, I/M readiness, monitor status, PIDs for
MIL_DIST, WARM_UPS, CLR_DIST, Mode $06 data.
Service technicians can use this mode to turn off the MIL after
a repair and to validate a repair.
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Mode $04 Clear DTCs and Diagnostic Information
The message format used to clear DTCs is as follows:
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Mode $05 Retrieve Oxygen Sensor Data
Mode $05 provides test results for oxygen sensors.
This mode is no longer used for CAN applications. All data is
still available using Mode $06.
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Mode $05 Retrieve Oxygen Sensor DataThe message format used to
retrieve oxygen sensor data is as follows:
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Mode $05 Retrieve Oxygen Sensor Data
D a t a B y t e
D e s c r i p t i o n
2 W h i c h T e s t I D : $ 0 0 - T e s t I D s s u p p o r t e
d - o p t i o n a l ( $ 0 1 t o $ 2 0 ) $ 0 1 - R i c h t o l e a n
s e n s o r t h r e s h o l d v o l t a g e ( c o n s t a n t ) $ 0
2 - L e a n t o r i c h s e n s o r t h r e s h o l d v o l t a g e
( c o n s t a n t ) $ 0 3 - L o w s e n s o r v o l t a g e f o r s
w i t c h t i m e c a l c u l a t i o n ( c o n s t a n t ) $ 0 4 -
H i g h s e n s o r v o l t a g e f o r s w i t c h t i m e c a l c
u l a t i o n ( c o n s t a n t ) $ 0 5 - R i c h t o l e a n s e n
s o r s w i t c h t i m e ( c a l c u l a t e d ) $ 0 6 - L e a n t
o r i c h s e n s o r s w i t c h t i m e ( c a l c u l a t e d ) $
0 7 - M i n i m u m s e n s o r v o l t a g e f o r t e s t c y c l
e ( c a l c u l a t e d ) $ 0 8 - M a x i m u m s e n s o r v o l t
a g e f o r t e s t c y c l e ( c a l c u l a t e d ) $ 0 9 - T i m
e b e t w e e n s e n s o r t r a n s i t i o n s ( c a l c u l a t
e d ) $ 0 A - $ 1 F - r e s e r v e d $ 2 0 - T e s t I D s s u p p
o r t e d - o p t i o n a l ( $ 2 1 t o $ 4 0 )
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Mode $06 Retrieve OBD test results and malfunction limits
Mode $06 provides monitoring test values and malfunction limits
for various OBD monitors.
Service technicians can use the data to see which monitors
failed and by how much, or to validate repairs.
Parts manufacturers can use this data to ensure replacement part
compatibility.
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Mode $06 Retrieve OBD test results and malfunction limits
Mode $06 test values and limits are un-scaled, decimal numbers
in J1850, ISO 9141-2 and ISO 1423-4. Manufacturers need to provide
conversion factors for technicians to utilize this data. ISO
15765-4 messages provide units and scaling as part of the message.
Generic scan tools will be able to convert these to engineering
units
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Mode $06 Retrieve OBD test results and malfunction limits
The message format used to retrieve OBD test results is as
follows:
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Mode $06 Retrieve OBD test results and limits
J1979 Secondary Air Mode $06 Data
Test ID Comp ID Description for J1850 Units
$30 $11 HO2S11 voltage for upstream flow test and rich limit
volts
$30 $21 HO2S21 voltage for upstream flow test and rich limit
volts
$31 $00 HO2S lean time for upstream flow test and time limit
seconds
Monitor ID Test ID Description for CAN Units
$71 $80 HO2S11 voltage for upstream flow test and rich limit
volts
$71 $81 HO2S21 voltage for upstream flow test and rich limit
volts
$71 $82 HO2S lean time for upstream flow test and time limit
seconds
Conversion for Test ID $30: multiply by 0.00098 to get volts
Conversion for Test ID $31: multiply by 0.125 to get seconds
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
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Mode $06 Retrieve OBD test results limits
J1979 DPFE EGR Hose Check Mode $06 Data
Test ID Comp ID Description for J1850 Units
$42 $11 Delta pressure for upstream hose test and threshold in.
H20
$42 $12 Delta pressure for downstream hose test and threshold
in. H20
Conversion for Test ID $42: Take value, subtract 32,768, and
then multiply result by 0.0078 to get inches of H20. The result can
be positive or negative.
Monitor ID Test ID Description for CAN Conventional DPFE
$31 $80 Delta pressure for upstream hose test and threshold
kPa
$31 $81 Delta pressure for downstream hose test and threshold
kPa
J1979 EGR Flow Check Mode $06 Data
Test ID Comp ID Description for J1850 Units
$49 $30 Delta pressure for flow test and threshold in. H20
$4B $30 EVR dutycycle for flow test and threshold percent
Conversion for Test ID $4B: multiply by 0.0000305 to get percent
dutycycle.
Conversion for Test ID $49: Take value, subtract 32,768, then
multiply result by 0.0078 to get inches of H20. The result can be
positive or negative.
Monitor ID Test ID Description for CAN Conventional DPFE
Units
$31 $85 Delta pressure for flow test and threshold kPa
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Mode $06 Retrieve OBD test results and malfunction limits
Example of Mode $06:TestID CompID Test Value Min Max
$10 $11 Cat monitor switch ratio 45 0 48
Bank 1
$10 $21 Cat monitor Switch ratio 42 0 48
Bank 2
Conversion: multiply by 0.0156 to get a value from 0 to 1.0Bank
1 = 45 * 0.0156 = 0.702
Bank 2 = 42 * 0.0156 = 0.655
Threshold = 48 * 0.0156 = 0.749
This catalyst is about to fail. A normal 100K catalyst should
have a 0 to 0.1
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Mode $07 Retrieve pending DTCs
Mode $07 reports pending, emission-related DTCs.
Starting in the 2005 MY, all pending DTCs must be reported, not
just continuous pending DTCs.
Staring in the 2005 MY, a pending DTC must be reported if the
last monitoring cycle had a malfunction.
Service technicians can use pending codes for faster validation
or a repair.
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Mode $07 Retrieve pending DTCs
The message format used to retrieve pending, emission-related
DTCs is as follows:
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September 28, 2002 Page 78
Mode $08 Request on-board device control
Mode $08 allows a service technician to invoke an on-board test
mode.
Only one test mode (Test ID $01) is currently defined. It allows
a service or an I/M technician to seal the evaporative system for a
pressure test.
On Ford systems, this closes the canister vent solenoid for a 10
minute time duration.
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September 28, 2002 Page 79
Mode $08 Request on-board device control
The message format used to request on-board device control is as
follows:
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September 28, 2002 Page 80
Mode $09 Retrieve vehicle information
Mode $09 allows a service tech or I/M test technician to obtain
vehicle VIN, module calibration number (CALID), Calibration
Verification Number (CVN).
VIN is required for 2005 MY, the vehicle can only report one
VIN.
CALID is required for 2005 MY. A unique CALID is required for
each emission-
related calibration on the vehicle. A unique CALID is required
even if only a bit if data changes.
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September 28, 2002 Page 81
Mode $09 Retrieve vehicle information (continued)
A CVN must be supplied for each CALID In 2005 MY, CVN must be
calculated every
driving cycle and stored in Keep Alive Memory so that it can be
retrieved with the engine off or engine running.
CVN must not be erased by Mode $04. CARB must approve CVN
algorithm. Manufacturers must provide CALID and CVN
information to facilitate I/M testing.
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September 28, 2002 Page 82
Mode $09 Retrieve vehicle information (continued)
Starting in the 2005 MY, CARB will require industry-standard
counters that display how often OBD monitors run during real-world
driving conditions as compared to a CARB-specified driving
cycle.
In-use performance counters will be required for catalyst, O2
sensor, EGR, secondary air, and evaporative system monitors.
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September 28, 2002 Page 83
Mode $09 Retrieve vehicle informationThe message format used to
retrieve vehicle information is as follows:
Info Type $02 is VIN, $04 is CALID(s), $06 is CVN(s), $08 is
in-use performance counters
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September 28, 2002 Page 84
Inspection/Maintenance Readiness
Many I/M test facilities will soon (Jan 1, 2002) be using OBD-II
diagnostic information in place of tailpipe emissions tests.
They will check MIL lamp, MIL status bit (PID 01, Data A, bit 7)
and OBD monitor readiness (PID 01).
For 2005 MY, they may check VIN, CALIDs and CVNs
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September 28, 2002 Page 85
Inspection/Maintenance Readiness (continued)
CALIDs ensure that the correct (not recalled) software is on the
vehicle.
CVNs ensure that the module software was not tampered with.
MIL status must not indicate MIL on during bulb prove out unless
the MIL is being commanded on by a confirmed DTC.
Monitor readiness bits must be in Keep Alive Memory
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September 28, 2002 Page 86
Inspection/Maintenance Readiness (continued)
I/M readiness status may be displayed to the customer using the
MIL.
After 15-20 seconds of MIL prove out, the MIL can blink for 5-10
seconds if the vehicle is not ready for I/M testing.
For the 2005 MY, CARB will require a scan tool communication
validation of every production calibration using a J1699-3
tool.
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September 28, 2002 Page 87
SAE/ISO Diagnostic Specifications Non-legislated diagnostic
messages are
defined by SAE J2190 and ISO 14229 These are commonly referred
to
manufacturer-specific test modes. Manufacturers can use these
messages to
perform manufacturer-specific tests and obtain
manufacturer-specific data from any control module.
Almost all manufacturers provide this info to the Equipment and
Tool Institute (ETI), the consortium of scan tool
manufacturers.
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September 28, 2002 Page 88
SAE/ISO Diagnostic Specifications Common uses for these messages
are:
Obtain manufacturer-specific PIDs Initiate on-board self-test
Obtain packets of PID data (rapid data) Control module outputs
Reprogram flash memory Configure modules
The J2190 messages are very similar to the J1979 messages in
structure and content.
Only physical addresses are used, responses are required.
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September 28, 2002 Page 89
J2190 Mode $13 Mode $13 reports all DTCs (emission and
non-emission, confirmed and pending.) Very similar to Mode
$03
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Request all codes Request
all powertrain DTCs (MIL, non-MIL, pending)
13
Report all codes Report all powertrain DTCs (MIL, non-MIL,
pending)
53 Code #1 or 00 00
Code #2 or 00 00
Code #3 or 00 00
No codes to report, exit normally without results General
Response 7F 13 00 00 00 62
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September 28, 2002 Page 90
J2190 Mode $14 Mode $14 clears all DTCs. Very similar to Mode
$04
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Request clear codes
Request clear all codes, (MIL, non-MIL, pending)
14
Confirm codes clear Confirm all codes were cleared (individual
clearing of codes not supported)
54
No codes to report, exit normally without results General
Response 7F 14 data
byte #2 data byte #3
00 12
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September 28, 2002 Page 91
J2190 Mode $22 Mode $22 is used to get PIDs. PID numbers,
scaling
and units are defined by manufacturer and are specific to their
individual systems.
Very similar to Mode $01 Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7
Request data by PID Request PID Access 22 PID
(high byte)
PID (low byte)
Report data by PID Report PID Data 62 PID
(high byte)
PID (low byte)
data 1 (opt)
data 2 (opt)
data 3 (opt)
data 4 (opt)
Invalid PID requested, request not supported General Response 7F
22 data
byte #2 data byte #3
00 12
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September 28, 2002 Page 92
J2190 Mode $23 Mode $23 is used to download data by direct
memory address. Test tool gets raw data.
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Request data by DMR
Request DMR Access EEC-V
23 address (high byte)
address (mid byte)
address (low byte)
Report data by DMR Report DMR Data EEC-V
63 address (high byte)
address (low byte)
data 1 (opt)
data 2 (opt)
data 3 (opt)
data 4 (opt)
Invalid DMR requested, request not supported General Response 7F
23 address
(high byte or high word MSB)
address (mid byte or high word LSB)
00 12
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September 28, 2002 Page 93
J2190 Mode $2AMode $2A is used to get a string of PIDs in one
message; a rapid packet.Used with Mode $2C to define rapid
packet.
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September 28, 2002 Page 94
J2190 Mode $30 Mode $30 is used to directly control module
outputs
like shift solenoids, IAC, AIR pump, EGR, etc. (requires Mode
$27 security access)
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Perform parameter
substitution Parameter Substitution 30 Chann.
ID Subst. Value high byte
Subst. Value low byte
Confirm diagnostic routine entered General Response 7F 30
Chann.
ID Subst. Value high byte
Subst. Value low byte
00
Invalid conditions, test running, or test not supported General
Response 7F 31 Test # 00 00 31, 22,
33, or 12
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September 28, 2002 Page 95
J2190 Mode $31 Mode $31 is used to request an on-board test,
based
on test number. Test Number On-demand Self Test Mode $81 Key On
Engine Off (gas and diesel) $82 Key on Engine Running (gas and
diesel) $84 Output Test Mode (gas and diesel) $88 Key On Engine
Running Glow Plug Test (diesel) $91 Key On Engine Off Injector Buzz
Test (diesel) $92 Key On Engine Running Cylinder Contribution Test
(diesel) $95 Key On Engine Running Switch Test (diesel) Data Bytes
(Hex)
#1 #2 #3 #4 #5 #6 #7 Perform diagnostic routine by test number
Diagnostic Routine Entry
31 Test #
Confirm diagnostic routine entered General Response
7F 31 Test # 00 00 00
Invalid conditions, test running, or test not supported General
Response 7F 31 Test # 00 00 22, or
12
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September 28, 2002 Page 96
J2190 Mode $36
Mode $36 is used for reprogramming. (requires Mode $27 security
access and Mode $34 Download Entry request)
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Request to enter download
mode Download Block Data 36 data 1 data 2
or 00 data 3 or 00
data 4 or 00
data 5 or 00
data 6 or 00
Not in download mode General Response
7F 36 data 1 data 2 data 3 22
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September 28, 2002 Page 97
J2190 Mode $3F
Mode $3F is used to indicate that the test tool is still online
and prevent a diagnostic session time-out.
Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7 Tester Present Tester
Present 3F Acknowledge tester General Response
7F 3F 00 00 00 00
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September 28, 2002 Page 98
J2190 Mode $7F Mode $7F is used by the control module to
respond
to a test tool request. Data Bytes (Hex) #1 #2 #3 #4 #5 #6 #7
General acknowledge General Response 7F Data
byte #1 of request
Data byte #2 of request
Data byte #3 of request
Data byte #4 of request
Ackn or Reject code
Acknowledge or Reject Code: $00 - General affirmative $10 -
General reject $11 - Mode not supported $12 - Invalid format,
sub-function not supported $21 - Busy, repeat request $22 -
Condition not correct, sequence error $23 - Routine not complete
$31 - Request out of range $33 - Access denied, device secured $34
- Access granted $50 - Upload not accepted $61 - Normal exit with
results $62 - Normal exit without results $63 - Abnormal exit with
results $64 - Abnormal exit without results
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September 28, 2002 Page 99
J1979 Message Traffic Example Clear DTCs (Mode 04)
TX MSG: J1850PWM 61 6A F1 04
RX MSG: J1850PWM 01 6B 10 44
Request PIDs (Mode 01) [PID $00 defines which PIDs are supported
]
TX MSG: J1850PWM 61 6A F1 01 00
RX MSG: J1850PWM 01 6B 10 41 00 BF 9F B9 10
Request PID 04 (LOAD_PCT)
TX MSG: J1850PWM 61 6A F1 01 04
RX MSG: J1850PWM 01 6B 10 41 04 00 [LOAD_PCT = 0%]
Request PID 05 (ECT)
TX MSG: J1850PWM 61 6A F1 01 05
RX MSG: J1850[PWM 01 6B 10 41 05 4A [ECT = 74 deg F]
Request PID 11 (TP)
TX MSG: J1850PWM 61 6A F1 01 11
RX MSG: J1850PWM 01 6B 10 41 11 32 [TP = 19%]
Request PID 1C (OBD Type)
TX MSG: J1850PWM 61 6A F1 01 1C
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September 28, 2002 Page 100
J1979 Message Traffic ExampleRequest Mode 09 info
TX MSG: J1850PWM 61 6A F1 09 00 [request Mode 09 items
supported]
RX MSG: J1850PWM 01 6B 10 49 00 01 FC 00 00 00
TX MSG: J1850PWM 61 6A F1 09 01
RX MSG: J1850PWM 01 6B 10 49 01 05 [number of VIN messages =
5]
TX MSG: J1850PWM 61 6A F1 09 02 [item 02 = VIN]
RX MSG: J1850PWM 01 6B 10 49 02 01 00 00 00 31
RX MSG: J1850PWM 01 6B 10 49 02 02 46 54 59 52
RX MSG: J1850PWM 01 6B 10 49 02 03 34 34 45 37
RX MSG: J1850PWM 01 6B 10 49 02 04 32 54 41 33
RX MSG: J1850PWM 01 6B 10 49 02 05 31 39 37 38 [VIN =
1FTYR44E72TA31978]
Request Pending DTCs (Mode 07)
TX MSG: J1850PWM 61 6A F1 07
RX MSG: J1850PWM 01 6B 10 47 01 13 01 02 00 00 [Pending DTC
P0113, P0102 detected]
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September 28, 2002 Page 101
J1979 Message Traffic Example
Request Freeze Frame Support (Mode 02) [PID $00 defines which
PIDs are supported ]
TX MSG: J1850PWM 61 6A F1 02 00 00
RX MSG: J1850PWM 01 6B 10 42 00 00 7F 98 00 00
Request Freeze Frame PID 02
TX MSG: J1850PWM 61 6A F1 02 02 00
RX MSG: J1850PWM 01 6B 10 42 02 00 01 13 [DTC that stored frame
= P0113]
Request DTCs (mode 03)
TX MSG: J1850PWM 61 6A F1 03 [No response to OBD request, no
DTCs]
Request DTCs (Mode 03)
TX MSG: J1850PWM 61 6A F1 03
RX MSG: J1850PWM 01 6B 10 43 01 13 00 00 00 00 [Stored DTC P0113
detected]
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September 28, 2002 Page 102
The End I hope this presentation took some of
the mystery out of diagnostic scan tool communication.
Thank you for your interest and attention!
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