
Diagnostic Procedure....................................... 1088
TROUBLE DIAGNOSIS FOR CONTROL UNIT
(EFP ROM)........................................................... 1089
Description ....................................................... 1089
Diagnostic Procedure....................................... 1090
TROUBLE DIAGNOSIS FOR
NON-DETECTABLE ITEMS................................ 1091
PNP, Overdrive Control, A/T Mode or
Accelerator Position Switches ......................... 1091
DIAGNOSTIC PROCEDURES FOR
SYMPTOMS......................................................... 1097
1. SPORT Indicator Lamp Does Not
Come On.......................................................... 1097
2. SPORT Indicator Lamp Does Not
Come On.......................................................... 1098
3. O/D OFF Indicator Lamp Does Not Come
On .................................................................... 1098
4. SPORT Indicator Lamp Does Not
Come On.......................................................... 1099
5. Engine Cannot Be Started In ªPº and ªNº
Position ............................................................ 1100
6. In ªPº Position, Vehicle Moves Forward Or
Backward When Pushed ................................. 1100
7. In ªNº Position, Vehicle Moves .................... 1101
8. Large Shock. ªNº®ªRº Position ................ 1102
9. Vehicle Does Not Creep Backward In ªRº
Position ............................................................ 1103
10. Vehicle Does Not Creep Forward In ªDº,
ª2º Or ª1º Position ............................................ 1104
11. Vehicle Cannot Be Started From D
1......... 1105
12. A/T Does Not Shift: D
1®D2Or Does Not
Kickdown: D
4®D2......................................... 1106
13. A/T Does Not Shift: D
2®D3.................... 1107
14. A/T Does Not Shift: D
3®D4.................... 1108
15. A/T Does Not Perform Lock-up ................. 1109
16. A/T Does Not Hold Lock-up Condition ...... 1110
17. Lock-up Is Not Released ........................... 1110
18. Engine Speed Does Not Return To Idle
(Light Braking D
4®D3) .................................. 1111
19. Vehicle Does Not Start From D
1............... 1112
20. A/T Does Not Shift: D
2®D1When
Depressing Accelerator Pedal ......................... 1113
21. A/T Does Not Shift: D
4®D3, When
Overdrive Control Switch ªONº®ªOFFº ........ 1114
22. A/T Does Not Shift: D
3®22, When
Selector Lever ªDº®ª2º Position ................... 1114
23. A/T Does Not Shift: 2
2®11, WhenSelector Lever ª2º®ª1º Position .................... 1115
24. Vehicle Does Not Decelerate By Engine
Brake ................................................................ 1115
TROUBLE DIAGNOSES Ð A/T Shift Lock
System................................................................. 1116
Description ....................................................... 1116
Wiring Diagram Ð SHIFT Ð ........................... 1117
Diagnostic Procedure....................................... 1118
Key Interlock Cable.......................................... 1121
Component Check ........................................... 1122
ON-VEHICLE SERVICE...................................... 1124
Control Valve Assembly and Accumulators .... 1124
Revolution Sensor Replacement ..................... 1125
Rear Oil Seal Replacement ............................. 1125
Parking Pawl Components Inspection ............. 1125
PNP Switch Adjustment ................................... 1125
Manual Control Linkage Adjustment................ 1126
REMOVAL AND INSTALLATION....................... 1127
Removal ........................................................... 1127
Installation ........................................................ 1128
MAJOR OVERHAUL........................................... 1129
Oil Channel ...................................................... 1131
Locations of Needle Bearings, Thrust Washers
and Snap Rings ............................................... 1132
DISASSEMBLY.................................................... 1133
REPAIR FOR COMPONENT PARTS................. 1144
Oil Pump .......................................................... 1144
Control Valve Assembly................................... 1148
Control Valve Upper Body ............................... 1154
Control Valve Lower Body ............................... 1159
Reverse Clutch ................................................ 1161
High Clutch ...................................................... 1165
Forward and Overrun Clutches ....................... 1167
Low & Reverse Brake ...................................... 1171
Forward Clutch Drum Assembly ...................... 1175
Rear Internal Gear and Forward Clutch Hub .. 1177
Band Servo Piston Assembly .......................... 1180
Parking Pawl Components .............................. 1184
ASSEMBLY.......................................................... 1186
Assembly (1) .................................................... 1186
Adjustment ....................................................... 1190
Assembly (2) .................................................... 1195
A/T FLUID COOLER SYSTEM........................... 1205
A/T Fluid Cooler ............................................... 1205
SERVICE DATA AND SPECIFICATIONS (SDS)1206
General Specifications ..................................... 1206
Specifications and Adjustment......................... 1206
When you read wiring diagrams:
+Read GI section, ªHOW TO READ WIRING DIAGRAMSº.
+See EL section, ªPOWER SUPPLY ROUTINGº for power distribution circuit.
When you perform trouble diagnoses, read GI section, ªHOW TO FOLLOW FLOW
CHART IN TROUBLE DIAGNOSESº.
AT-1002

Shift Mechanism
The automatic transmission uses compact, dual planetary gear systems to improve power-transmission
efficiency, simplify construction and reduce weight.
It also employs an optimum shift control and superwide gear ratios. They improve starting performance and
acceleration during medium and high-speed operation.
Two one-way clutches are also employed: one is used for the forward clutch and the other for the low clutch.
These one-way clutches, combined with four accumulators, reduce shifting shock to a minimum.
CONSTRUCTION
V1Torque converter clutch piston
V2Torque converter
V3Oil pump
V4Input shaft
V5Brake band
V6Reverse clutch
V7High clutch
V8Front pinion gear
V9Front sun gear
V10Front internal gear
V11Front planetary carrier
V12Rear sun gear
V13Rear pinion gear
V14Rear internal gear
V15Rear planetary carrier
V16Forward clutch
V17Forward one-way clutch
V18Overrun clutch
V19Low one-way clutch
V20Low & reverse brake
V21Parking pawl
V22Parking gear
V23Output shaft
FUNCTION OF CLUTCH AND BRAKE
Control members Abbr. Function
V6Reverse clutch R/C To transmit input power to front sun gearV9.
V7High clutch H/C To transmit input power to front planetary carrierV11.
V16Forward clutch F/C To connect front planetary carrierV11with forward one-way clutchV17.
V18Overrun clutch O/C To connect front planetary carrierV11with rear internal gearV14.
V5Brake band B/B To lock front sun gearV9.
V17Forward one-way clutch F/O.CWhen forward clutch is engaged, to stop rear internal gearV14from rotating in oppo-
site direction.
V19Low one-way clutch L/O.C At D1position, to prevent rear internal gearV14from rotating in opposite direction.
V20Low & reverse brake L & R/BTo lock rear internal gearV14(2, 12and 11), to lock front planetary carrierV11(R
position).
SAT509I
OVERALL SYSTEM
AT-1024

CLUTCH AND BAND CHART
Shift positionV6
Reverse
clutchV7
High
clutchV16Forward
clutchV18Overrun
clutchBand servo
V17Forward
one-
way
clutchV19Low
one-
way
clutchV20Low &
reverse
brakeLock-up Remarks
2nd
apply3rd
release4th
apply
PPARK
POSITION
R
jjREVERSE
POSITION
NNEUTRAL
POSITION
D*41st
j*1jVX++
Automatic shift
1«2«3«4 2ndj*1jVj+
3rdjj*1jV*2^^+
4thj^*3^^jj
21stjjVX++Automatic shift
1«2
2nd
j*1jVj+
11stjj+jLocks (held sta-
tionary)
in 1st speed
1¬2 2nd
jjj+
*1: Operates when overdrive control or A/T mode switch is being set in ªOFFº or ªSPORTº position.
*2: Oil pressure is applied to both 2nd ªapplyº side and 3rd ªreleaseº side of band servo piston. However, brake band does not contract because oil
pressure area on the ªreleaseº side is greater than that on the ªapplyº side.
*3: Oil pressure is applied to 4th ªapplyº side in condition *2 above, and brake band contracts.
*4: A/T will not shift to 4th when overdrive control or A/T mode switch is set in ªOFFº or ªSPORTº position.
j: Operates
: Operates when throttle opening is less than 5.5/16, activating engine brake.
*: Operates during ªprogressiveº acceleration.
^: Operates but does not affect power transmission.
jVX: Operates when throttle opening is less than 5.5/16, but does not affect engine brake.
jV
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-1025

Control System
OUTLINE
The automatic transmission senses vehicle operating conditions through various sensors. It always controls
the optimum shaft position and reduces shifting and lock-up shocks.
SENSORSTCMACTUATORS
PNP switch
Accelerator position sensor
Accelerator position switch
(Full accel, off accel position
switch)
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed sensor
Overdrive control switch
A/T mode switch
c
Shift control
Line pressure control
Lock-up control
Overrun clutch control
Timing control
Fail-safe control
Self-diagnosis
Duet-EU control
CONSULT-II communication line
control
c
Shift solenoid valve A
Shift solenoid valve B
Overrun clutch solenoid valve
Torque converter clutch
solenoid valve
Line pressure solenoid valve
SPORT indicator lamp
CONTROL SYSTEM
SAT207K
OVERALL SYSTEM
AT-1026

TCM FUNCTION
The function of the TCM is to:
+Receive input signals sent from various switches and sensors.
+Determine required line pressure, shifting point, lock-up operation, and engine brake operation.
+Send required output signals to the respective solenoids.
INPUT/OUTPUT SIGNAL OF TCM
Sensors and solenoid valves Function
InputPNP switch Detects select lever position and sends a signal to TCM.
Accelerator position sensor Detects throttle valve position and sends a signal to TCM.
Accelerator position switch
(Off accel)Detects throttle valve's fully-closed position and sends a signal to TCM.
Accelerator position switch
(Full accel)Detects a throttle valve position of greater than 1/2 of full throttle and sends a
signal to TCM.
Engine speed signal From ECM.
A/T fluid temperature sensor Detects transmission fluid temperature and sends a signal to TCM.
Revolution sensor Detects output shaft rpm and sends a signal to TCM.
Vehicle speed sensorUsed as an auxiliary vehicle speed sensor. Sends a signal when revolution sen-
sor (installed on transmission) malfunctions.
Overdrive control switch
A/T mode switchSends a signal, which prohibits a shift to ªD
4º (overdrive) position, to the TCM.
OutputShift solenoid valve A/BSelects shifting point suited to driving conditions in relation to a signal sent from
TCM.
Line pressure solenoid valveRegulates (or decreases) line pressure suited to driving conditions in relation to
a signal sent from TCM.
Torque converter clutch solenoid valveRegulates (or decreases) lock-up pressure suited to driving conditions in relation
to a signal sent from TCM.
Overrun clutch solenoid valveControls an ªengine brakeº effect suited to driving conditions in relation to a sig-
nal sent from TCM.
O/D OFF indicator lamp
SPORT indicator lampShows TCM faults, when A/T control components malfunction.
OVERALL SYSTEM
Control System (Cont'd)
AT-1027

Diagnosis by CONSULT-II
NOTICE
1.The CONSULT-II electrically displays shift timing and lock-up timing (that is, operation timing of each
solenoid).
Check for time difference between actual shift timing and the CONSULT-II display. If the difference is
noticeable, mechanical parts (except solenoids, sensors, etc.) may be malfunctioning. Check mechanical
parts using applicable diagnostic procedures.
2. Shift schedule (which implies gear position) displayed on CONSULT-II and that indicated in Service
Manual may differ slightly. This occurs because of the following reasons:
+Actual shift schedule has more or less tolerance or allowance,
+Shift schedule indicated in Service Manual refers to the point where shifts start. Gear position dis-
played on CONSULT-II indicates the point where shifts are completed.
3. Shift solenoid valve ªAº or ªBº is displayed on CONSULT-II at the start of shifting. Gear position is dis-
played upon completion of shifting (which is computed by TCM).
4. Additional CONSULT-II information can be found in the Operation Manual supplied with the CONSULT-II
unit.
SELF-DIAGNOSTIC RESULT TEST MODE
Refer to AT-1028.
DATA MONITOR DIAGNOSTIC TEST MODE
Item DisplayMonitor item
Description Remarks TCM
input
signalsMain
signals
Vehicle speed sensor 1 (A/T)
(Revolution sensor)VHCL/S SEzA/T
[km/h] or [mph]
XÐ+Vehicle speed computed from
signal of revolution sensor is
displayed.When racing engine in ªNº or ªPº
position with vehicle stationary,
CONSULT data may not indicate
0 km/h (0 MPH).
Vehicle speed sensor 2
(Meter)VHCL/S SEzMTR
[km/h] or [mph]
XÐ+Vehicle speed computed from
signal of vehicle speed sensor
is displayed.Vehicle speed display may not be
accurate under approx. 10 km/h
(6 MPH). It may not indicate 0
km/h (0 MPH) when vehicle is
stationary.
Accelerator position sensor THRTL POS SEN
[V]XÐ+Accelerator position sensor sig-
nal voltage is displayed.
A/T fluid temperature sensor FLUID TEMP SE
[V]
XÐ+A/T fluid temperature sensor
signal voltage is displayed.
+Signal voltage lowers as fluid
temperature rises.
Battery voltage BATTERY VOLT
[V]XÐ+Source voltage of TCM is dis-
played.
Engine speed ENGINE SPEED
[rpm]
XX+Engine speed, computed from
engine speed signal, is dis-
played.Engine speed display may not be
accurate under approx. 800 rpm.
It may not indicate 0 rpm even
when engine is not running.
Overdrive control switch OVERDRIVE SW
[ON/OFF] X Ð+ON/OFF state computed from
signal of overdrive control SW
is displayed.
P/N position switch PN POSI SW
[ON/OFF] X Ð+ON/OFF state computed from
signal of PN position SW is dis-
played.
R position switch R POSITION SW
[ON/OFF] X Ð+ON/OFF state computed from
signal of R position SW is dis-
played.
D position switch D POSITION SW
[ON/OFF] X Ð+ON/OFF state computed from
signal of D position SW is dis-
played.
2 position switch 2 POSITION SW
[ON/OFF] X Ð+ON/OFF status, computed from
signal of 2 position SW, is dis-
played.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
AT-1034

Introduction
The TCM receives a signal from the vehicle-speed sensor, accel-
erator position sensor or PNP switch and provides shift control
or lock-up control via solenoid valves.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good
operating condition and be free of valve seizure, solenoid valve
malfunction, etc.
It is much more difficult to diagnose a problem that occurs inter-
mittently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A
road test with CONSULT-II or a circuit tester connected should
be performed. Follow the ªWork Flowº. Refer to AT-1040.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The
customer can supply good information about such problems,
especially intermittent ones. Find out what symptoms are present
and under what conditions they occur. A ªDiagnostic Worksheetº
like the example (AT-1038) should be used.
Start your diagnosis by looking for ªconventionalº problems first.
This will help troubleshoot driveability problems on an electroni-
cally controlled engine vehicle.
SAT631IA
SAT632I
SEF234G
TROUBLE DIAGNOSIS Ð Introduction
AT-1036

Diagnostic Worksheet
INFORMATION FROM CUSTOMER
KEY POINTS
WHAT...................... Vehicle & A/T model
WHEN..................... Date, Frequencies
WHERE.................. Road conditions
HOW....................... Operating conditions, Symptoms
Customer name MR/MS Model & Year VIN
Trans. model Engine Mileage
Incident Date Manuf. Date In Service Date
FrequencyNContinuousNIntermittent ( times a day)
SymptomsNVehicle does not move. (NAny positionNParticular position)
NNo up-shift (N1st®2ndN2nd®3rdN3rd®O/D)
NNo down-shift (NO/D®3rdN3rd®2ndN2nd®1st)
NLockup malfunction
NShift point too high or too low.
NShift shock or slip (NN®DNLockupNAny drive position)
NNoise or vibration
NNo kickdown
NNo pattern select
NOthers
()
SPORT indicator lamp Blinks for about 8 seconds.
NContinuously litNNot lit
Malfunction indicator (MI)NContinuously litNNot lit
TROUBLE DIAGNOSIS Ð Introduction
AT-1037