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No part of any ATSG publication may be reproduced, stored in any retrieval system or transmitted in any form or by any means, including but not limited to electronic, mechanical, photocopying, recording or otherwise,without written permission of Automatic Transmission Service Group. This includes all text illustrations,tables and charts.
"ATSG would like to thank Honda Motor Co. for the illustrationsand information contained in this manual."
The information and part numbers contained in this booklet havebeen carefully compiled from industry sources known for their
reliability, but ATSG does not guarantee its accuracy.
The USA built BAXA and the Japan built MAXA and the M6HA transaxle is part of a new generation of 3 shafttransaxles. The features that make these units unique are the use of 6 solenoids, 2 pressure switches and NO one-way clutches.This new generation transaxle's PCM has a unique solenoid strategy to control shift overlap for upshifts anddownshifts. The PCM also requires a full complement of sensors to control shift timing and shift feel.All pertinent information for tear-down and assembly as well as some electrical diagnosis, covering 1997 to2001 models, has been included in this manual.
AUTOMATIC TRANSMISSION SERVICE GROUP 18639 S.W. 107TH AVENUEMIAMI, FLORIDA 33157
L T O D 4 " 1 s t " G E A R S O L E N O I D A P P L I C A T I O N
N E U T R A L
N E U T R A L T O
D 4 - 1 s t G E A R T R A N S I T I O N
D 4 - 1 s t G E A R
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
G e a r
G e a r
G e a r
P r e s s u r e M o d e
P r e s s u r e M o d e
P r e s s u r e M o d e
S C
S " A "
S C
S " A "
S C
S " A "
S C S " B "
S C S " B "
S C S " B "
S C S " C "
S C S " C "
S C S " C "
C P C S " A "
C P C S " A "
C P C S " A "
C P C S " B "
C P C S " B "
C P C S " B "
L U C S
L U C S
L U C S
N D 4
D 4
N 1 s t
1 s t
O F F
O N
O F F
O N
O N
O N
O F F
O N
O N
O F F
m o d u l a t i n g
O F F
O F F
O F F
O F F
O F F
O F F
O F F
n / a
C P C
L I N E
S u m m a r y : S h i f t S o l e n o i d s " A " a n d " C " a r e t u
r n e d O N t o c o n n e c t 1 s t c l u t c h a p p l y o i l t o t h e s p r i n g s i d e a n d c e n t e r o f
C P C v a l v e " A . " C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " A " o i l m o d u l a t e s o n t h e b o r e p l u g s i d e o f C P C v a l v e " A "
t o c o n t r o l 1 s t c l u t c h a p p l i c a t i o n . T h e 1 s t c l u t c h i s a p p l i e d w i t h r e d u c e d p r e s s u r e , w h i c h i s C P C m o d e .
S u m m a r
y : S h i f t S o l e n o i d " A " i s t u r n e d O F F w
h i c h s w i t c h e s t h e p o r t o n S h i f t V a l v e " A " f r o m C P C t o L i n e P r e s s u r e .
1 s t C l u t c
h p r e s s u r e i s n o w L i n e P r e s s u r e
" 1 s t " T O " 2 n d " U P S H I F T A N D " 2 n d " G E A R S O L E N O I D A P P L I C A T I O N
D 4 - 1 s t G E A R
D 4 - 1 s t T O 2 n d G E A R T R A N S I T I O N
D 4 - 2 n d G E A R
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
G e a r
G e a r
G e a r
P r e s s u r e M o d e
P r e s s u r e M o d e
P r e s s u r e M o d e
S C S " A "
S C S " A "
S C S " A "
S C S " B "
S C S " B "
S C S " B "
S C S " C "
S C S " C "
S C S " C "
C P C S " A "
C P C S " A "
C P C S " A "
C P C S " B "
C P C S " B "
C P C S " B "
L U C
S
L U C
S
L U C
S
D 4
D 4
D 4
2 n d
2 n d
1 s t
O N
O N
O F F
O N
O N
O N
O N
O N
O N
O N
m o d u l a t i n g
m o d u l a t i n g
O F F
O F F
O F
F
O F
F
O F F
O F
F
C P C
L I N E
L I N E
S u m m a r y : S h i f t S o l e n o i d s " A " a n d " C " a r e t u r n e d O N t o c o n n e c t 1 s t c l u t c h a p p l y o i l t o t h e s p r i n g s i d e a n d c e n t e r o f
C P C v a
l v e " A . " C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " A " o i l m o d u l a t e s o n t h e b o r e p l u g s i d e o f C P C v a l v e " A "
w h i c h t u r n s 1 s t c l u t c h p r e s s u r e b a c k t o C P C m o d e . C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " B " o i l m o d u l a t e s o n t h e
b o r e p l u g s i d e o f C P C v a l v e
" B " w h i c h c o n t r o l s t h e a p p l i c a t i o n o f
t h e 2 n d c l u t c h .
S u m m a r y : S h i f t S o l e n o i d " C " i s t u r n e d O F
F w h i c h s w i t c h e s 2 n d c l u t c h p r e s s u r e
t o L i n e p r e s s u r e m o d e v i a t h e
M a n u a l v a l v e , a n d c o n n e c t s t h e 1 s t c l u t c h t o a n e x h a u s t v i a S h i f t V a l v e " C . " C l u t c h
P r e s s u r e C o n t r o l S o l e n o i d v a l v e
" A " i s t u r n e d o n t o b l o c k
p r e s s u r e f r o m t h e b o r e p l u g s i d e o f C P
S u m m a r y : S h i f t S o l e n o i d " B " i s t u r n e d O F
F , w h i c h s t r o k e s S h i f t V a l v e B , t o c o n n e c t t h e 2 n d c l u t c h b a c k t o C P C
v a l v e
" B . " 2 n d c l u t c h p r e s s u r e i s c h a n g e d t o C P C m o d e t h r u t h e m o d u l a t i o n o f C l u t c h P r e s s u r e C o n t r o l S o l e n o i d
v a l v e "
B " a c t i n g o n t h e b o r e p l u g s i d e o f C P C v a l v e " B . " C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " A " a c t i n g o n t h e
b o r e p l u g s i d e o f C P C v a l v e " A " c o n t r o l s t h e a p p l i c a t i o n o f t h
e 3 r d c l u t c h .
S u m m
a r y : S h i f t S o l e n o i d " C " i s t u r n e d O N w h i c h s t r o k e s S h i f t V a l v e " C " a n d s w i t c h e s 3 r d c l u t c h p r e s s u r e t o L i n e
p r e s s u r e m o d e v i a t h e M a n u a l v a l v e ,
a n d c o n n e c t s t h e 2 n d c l u t c h t o a n e x h
N D " 4 t h " G E A R S O L E N O I D A P P L I C A T I O N
D 4 - 3 r d T
O 4 t h G E A R T R A N S I T I O N
D 4 - 4 t h G E A R
D 4 - 3 r d G E A R
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
S e l e c t o r p o s i t i o n
G e a r
G e a r
G e a r
P r e s s u r e M o d e
P r e s s u r e M o d e
P r e s s u r e M o d e S
C S " A "
S
C S " A "
S
C S " A "
S C S " B "
S C S " B "
S C S " B "
S C S " C "
S C S " C "
S C S " C "
C P C S " A "
C P C S " A "
C P C S " A "
C P C S " B "
C P C S " B "
C P C S " B "
L U C
S
L U C
S
L U C
S
D 4
D 4
D 4
4 t h
4 t h
2 n d
O F F
O F F
O N
O F F
O F F
O F F
O N
O N
O F F
O N
O F F
m o d u l a t i n g
m o d u l a t i n g
O F
F
O F
F
O F
F
O F F
O N
C P C
L I N E
L I N E
S u m m
a r y : S h i f t S o l e n o i d " A " i s t u r n e d O F F , w h i c h s t r o k e s S h i f t V a l v e " A , " t o c o n n e c t t h e 3 r d c l u t c h b a c k t o C P C
v a l v e
" A " . " 3 r d c l u t c h p r e s s u r e i s t u r n e d t o C P C m o d e t h r u t h e m o d u l a t i o n o f C l u t c h P r e s s u r e C o n t r o l S o l e n o i d
v a l v e " A " a c t i n g o n t h e b o r e p l u g s i d e o f C P C v a l v e " A . " C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " B " o i l a c t s o n t h e
b o r e p l u g s i d e o f C P C v a l v e " B " w h i c h c o n t r o l s t h e a p p l i c a t i o n o f t h e 4 t h c l u t c h .
S u m m a
r y : S h i f t S o l e n o i d " C " i s t u r n e d O F F
w h i c h s t r o k e s S h i f t v a l v e " C . " T h i s s w
i t c h e s 4 t h c l u t c h p r e s s u r e t o L i n e
p r e s s u r e v i a t h e M a n u a l v a l v e . C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " A " i s O N t o b l o c k p r e s s u r e t o t h e b o r e p l u g
s i d e o f C P C v a l v e " A . " T h e 3 r d c l u t c h i s c o n n e c t e d t o a n e x h a u s t v i a S h i f t V a l v e " C . "
LOCK-UP CONTROLThe Lock-up Solenoid is an 'ON/OFF" solenoid which strokes the lock-up shift valve to turn lock-up "ON".The PCM/TCM controls lock-up apply feel by the use of the A/T Clutch Pressure Control Solenoids actingon the lock-up control and timing valves as soon as the Lock-up Solenoid is turned "ON" providing partialand full lock-up. Accord models attain lock-up in 3rd and 4th gears. Prelude models attain lock-up in 2nd,3rd and 4th gears.
D 4 - 4 t h G E A R - T C C A P P L I E D
S e l e c t o r p o s i t i o n
G e a r
P r e s s u r e M o d e
S C S " A "
S C S " B "
S C S " C "
C P C S " A "
C P C S " B " L U C S
D 4
4 t h
O F F
O F F
O N
m o d u l a t i n g
O N
O F F
L I N E
S u m m a r y : T h e L o c k - u p C o n t r o l S o l e n o i d i s t u r n e d O N w h i c h d r a i n s t h e o i l o n t h e
s p r i n g s i d e o f
t h e L o c k - u p s h i f t v a l v e . T h e c o m p u t e r c o n t r o
l s t h e s w i t c h i n g o f P a r t i a l , H a l f , a n d F
u l l C o n v e r t e r
C l u
t c h a p p l i c a t i o n t h r u t h e m o d u l a t i o n o f t h e C l u t c h P r e s s u r e C o n t r o l S o l e n o i d
v a l v e " A "
a c t i n g o n t h e L o c k - u p t i m i n g a n d c o n t r o l v a l v e . E x a m p l e : W h e n C l u t c h P r e s s u r e C o n t r o l
S o
l e n o i d v a l v e " A " p r e s s u r e i s l o w , a n d t h e L o c k - u p C o n t r o l S o l e n o i d i s O N , t h e T o r q u e
C o
n v e r t e r C l u t c h i s a p p l i e d p a r t i a l l y . W h
e n C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " A "
S u m m a r y : T h e L o c k - u p C o n t r o l S o l e n o i d i s t u r n e d O N w h i c h d r a i n s t h e o i l o n t h e
s p r i n g s i d e o f
t h e L o c k - u p s h i f t v a l v e . T h e c o m p u t e r c o n t r o
l s t h e s w i t c h i n g o f P a r t i a l , H a l f , a n d F
u l l C o n v e r t e r
C l u
t c h a p p l i c a t i o n t h r u t h e m o d u l a t i o n o f t h e C l u t c h P r e s s u r e C o n t r o l S o l e n o i d
v a l v e " B "
a c t i n g o n t h e L o c k - u p t i m i n g a n d c o n t r o l v a l v e . E x a m p l e : W h e n C l u t c h P r e s s u r e C o n t r o l
S o
l e n o i d v a l v e " B " p r e s s u r e i s l o w , a n d t h e L o c k - u p C o n t r o l S o l e n o i d i s O N , t h e T o r q u e
C o
n v e r t e r C l u t c h i s a p p l i e d p a r t i a l l y . W h
e n C l u t c h P r e s s u r e C o n t r o l S o l e n o i d v a l v e " B "
Summary: When Shift Control Solenoid "B" and "C" are OFF, oil from the Modulating valve isapplied to stroke the valves that the solenoids control.
CONNECTED
CONNECTED
CONNECTED
CONNECTED
Summary: When Shift Control Solenoid "B" and "C" are ON, oil from the Modulatingvalve is blocked at the end of the solenoid. The valves, that the solenoids control, are
connected to the exhaust at the top of the solenoid.
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE OPERATION "OFF"
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE OPERATION "ON"
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE "B"
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE "A"
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE "A"
CLUTCH PRESSURE CONTROL SOLENOID AND VALVE "B"
CLUTCH PRESSURECONTROL
SOLENOIDS "OFF"
CLUTCH PRESSURECONTROL
SOLENOIDS "ON"
X
X
X
X
Clutch Pressure Control Solenoid and Valve "A" supply modulating pressure to CPC valve "A", ReverseCPC valve and Shift valve "C" when "OFF."
Clutch Pressure Control Solenoid and Valve "B" shut off the supply of modulating pressure to CPC valve
Clutch Pressure Control Solenoid and Valve "A" shut off the supply of modulating pressure to CPC valve"A", Reverse CPC valve and Shift valve "C" when "ON."
Clutch Pressure Control Solenoid and Valve "B" supply modulating pressure to CPC valve "B", Shiftvalve "C" and Shift Valve "D" when "ON."
CLUTCH PRESSURE CONTROLThe PCM/TCM regulates the A/T Clutch Pressure Control Solenoids "A" and "B" thereby controllingall clutch apply pressure via the clutch pressure control (CPC) valves as well as lock-up apply
pressure.
SOLENOID CONTROL
SEQUENTIAL SPORTSHIFT MODE (PRELUDE ONLY)When in the D4 position, while sliding the shift lever to the Sequential Sportshift Mode position, thedriver can use the shift lever to upshift and downshift similar to the operation of a manualtransmission.Pushing the shift lever towards the "+" indicator results in an upshift to the next higher gear.Pushing the shift lever towards the "-" indicator results in a downshift to the next lower gear.The number of the selected gear is displayed in the shift indicator next to the D4 indicator as seenbelow. The transmission does not automatically shift, it remains in the selected gear position.
The transmission will upshift or downshift automatically under the following conditions:1. Downshift from 4th to 3rd when more power is required such as when climbing a hill.2. Provide engine braking when on a steep incline.3. Downshift to 1st gear when the vehicle comes to a stop.4. Under proper conditions, the PCM/TCM will allow a downshift to avoid engine overreving.5. A coast downshift will occur to a lower gear when vehicle speed drops low enough to require the
downshift signal at which time the shift indicator will flash several times to indicate a lower gear position.
The PCM/TCM compares actual driving conditions with memorized driving conditions, by the use of aFuzzy Logic System and input from various sensors to control shifting while the vehicle is ascending ordescending a hill, or during speed reduction.
ASCENDING CONTROLWhen the computer determines that the vehicle is climbing a hill in the D4 or D3 positions, the GradeLogic System extends the engagement area of 2nd and 3rd gear to prevent the transmission fromfrequently shifting between 2nd and 3rd gears, and between 3rd and 4th gears in order to shiftbusyness and to also have adequate power.Shift schedules stored in the computer between 2nd and 3rd gears, and between 3rd and 4th gears,enable the computer's Fuzzy Logic to automatically select the most suitable gear according to how steepthe hill is as shown in the graph below.
DESCENDING CONTROLWhen the computer determines that the vehicle is going down a hill in D4 or D3 positions, the closedthrottle upshift speed from 3rd to 4th gear and from 2nd to 3rd becomes faster than the set speed for flat
road driving to widen the 3rd and 2nd gear driving area. This in conjunction with engine braking fromdeceleration lock-up, achieves smooth driving when the vehicle is descending. There a two descendingmodes with different 3rd and 2nd gear driving areas depending on the gradient encountered as seen inthe graph below.
GRADE LOGIC CONTROL SYSTEM
DECELERATION CONTROLWhen the vehicle turns a corner and needs to decelerate first and then accelerate, the computer sets thedata for deceleration control to reduce the number of times the transmission shifts. When the vehicle isdecelerating from speeds above 27 mph (43 km/h), the computer shifts the transmission from 4th to 2ndgear earlier than normal to cope with upcoming acceleration.
IMPORTANT NOTE:
NEVER ROAD TEST A VEHICLE EQUIPPED WITH GRADE LOGIC CONTROL ON ALIFT!
THE VEHICLE WILL SHIFT HUNT AND/OR SKIP A GEAR, THE GRADE CONTROLSYSTEM BECOMES CONFUSED WITH THE WHEELS OFF THE GROUND AND WILLCOMMAND THE SHIFT SOLENOIDS IN SUCH A MANNER THAT IT WILL APPEAR TOBE A TRANSMISSION MALFUNCTION!
RETRIEVE CODES When the PCM/TCM senses an abnormality, the "D4" Lamp will begin to flash steadily as seen below.
In some instances the "MIL" Lamp will also be illuminated, check for those related codes first.Connect an OBD-II scan tool conforming to SAE J1978, to the Data Link Connector (DLC), as shownbelow, and check for codes in the generic category, and the transmission control system as well asany other system codes that may be pertinent. Also check for recorded freeze frame information andrefer to the code chart shown beginning on page15.
RETRIEVE CODES When the PCM/TCM senses an abnormality, the "D4" Lamp will begin to flash steadily as seen below.The Prelude offers two methods of code retrieval:
1. Connect an OBD-II compliant scan tool to the 16 pin Data Link Connector (DLC) shown, below left.2. Locate the 2 pin Service Check Connector, shown below right, and jump the SCS connector with the tool shown or a suitable substitute and read the "flash" codes shown in () found in the code chart beginning on page 15.
The "flash" code format is shown directly below. Single digit codes are indicated by individual shortflashes.Two digit codes are indicated by long flashes followed by short flashes.
CODE CLEARING PROCEDURE (PRELUDE)
CLEAR CODES Reset the PCM/TCM memory with the scan tool or remove the 7.5 AMP BACK-UP FUSE from theunder hood fuse box for at least 10 seconds as shown below.
IMPORTANT NOTE:Remember to obtain the radio anti-theft codes so they may reinstalled in the event they are lost during thecode clearing process.
·No Lock-up (Prelude Only) ·Loss of Engine RPM Signal·Faulty Distributor/Ignition Coil·Wire or Connection·Faulty Ignition Coil
P0730(41)
OFF ON
·Failure to shift through the gears·Skipped Shifts
·Mechanically Bad Shift Solenoids·Mechanically Bad A/T Pressure·Control Solenoids·Low Clutch Pressure·Internal Component Slipping
P0740(40)
OFF ON
·Lock-up Clutch Does Not Apply·Lock-up Clutch Does Not Disengage
·Mechanically Bad Lock-up·Control Solenoid·Mechanically Bad A/T Pressure·Control Solenoids·Lock-up Shift, Control or Timing Valve Problems·Faulty Torque Converter ·Faulty Speed Sensor
P0753(7) ONFLASHES
FLASHES
·Does Not Shift, Stuck in 4th Gear ·Fails to Shift to 4th Gear ·Erratic Shifting
·Electrically Bad Shift Solenoid 'A'·Shift Solenoid "A" Circuit Fault
P0758(8)
FLASHES ON
·Electrically Bad Shift Solenoid 'B'·Shift Solenoid "B" Circuit Fault
·3rd Gear Starts·Fails to Shift to 1st or 2nd Gear ·Erratic Shifting
·Late Shift From N to D or N to R·Excessive Shock or Flare on 1-2,2-3 or 3-4 Shift
·Excessive Shock or Flare on 2-1, 3-2 or 4-3 Shift
P0780(45)
FLASHES ON
·Incorrect Gear Ratio·Mechanical Problem in Hydraulic System
·Mechanical Fault with ShiftSolenoid A, B or C
·Mechanical Fault with A/TPressure Control Solenoid A or B
·Internal Hydraulic Leak
*DTC's in parentheses is the code the D4 Lamp will flash when the 2 pin Service Connector is jumped (Prelude Only), or a Scan Tool capable of displaying flash codes is connected to the16 pin DLC
·Mechanical Fault with A/TPressure Control Solenoid A or B
·Mechanical Fault with ShiftSolenoid 'B'
·Internal Hydraulic Leak
*DTC's in parentheses is the code the D4 Lamp will flash when the 2 pin Service Connector is jumped (Prelude Only), or a Scan Tool capable of displaying flash codes is connected to the16 pin DLC **The D4 Indicator Lamp cannot flash code (37) even when the Service Check Connector is jumped.
*DTC's in parentheses is the code the D4 Lamp will flash when the 2 pin Service Connector is jumped (Prelude Only), or a Scan Tool capable of displaying flash codes is connected to the16 pin DLC
*DTC D4 LAMP MIL LAMP SYMPTOM POSSIBLE CAUSE
P01753(1) ON
·Lock-up Does Not Apply ·Short or Open in Lock-up
Solenoid Circuit·Faulty Lock-up Solenoid
P01768(16)
ON
P01773(23)
P01790(3)
FLASHES ON
FLASHES
FLASHES
·A/T Clutch Pressure Control Solenoid 'A' Circuit Fault·Faulty A/T Clutch Pressure Control Solenoid 'A'
·Excessive Shock or Flares on Shifts·Lock-up Clutch Does Not Operate Smoothly·Lock-up Clutch does Not Apply
NOTE: Use of a fluid other than the recommended fluidmay cause shift quality concerns.If this is so, a friction modifier added to this fluid may benecessary.
HONDA ACCORD1998 & LATER WITH BAXA/MAXA TRANSMISSION
DELAY IN REVERSE AND 1-2 BIND-UPHARSH DRIVE ENGAGEMENT
COMPLAINT:
CAUSE:
CORRECTION:
The transmission has been overhauled, and after the transmission is installed back intothe vehicle, the transmission delays in reverse and binds up on the 1-2 shift. A harshengagement into drive will also occur.
During the installation of the transmission the connectors for shift solenoids "B" and"C" were switched with the connectors for A/T Clutch Pressure Control solenoids "A"and "B".These connectors are identical in configuration (Refer to Figures 2 & 3) which permits
the cross connection of these solenoid connectors causing the above complaints.
When reconnecting these solenoid connectors, use the chart in figure 1 to insure thecorrect solenoid connections have been made.
NOTE: There are other Honda/Acura transaxles that are very similar to theBAXA/MAXA, causing the same possibility of cross connecting Shift Solenoid "A"and "B" connectors with A/T Clutch Pressure Control Solenoid connectors, these arelisted below: