TROUBLE DIAGNOSIS — INTRODUCTION
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TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionECS004QO
The TCM receives a signal from the vehicle speed sensor, throttle
position sensor or PNP switch and provides shift control or lock-up
control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with the EURO-OBD related parts
of the A/T system for malfunction-diagnostic purposes. The TCM is
capable of diagnosing malfunctioning parts while the ECM can store
malfunctions in its memory.
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 oper-
ating condition and be free of valve seizure, solenoid valve malfunc-
tion, etc.
It is much more difficult to diagnose a problem that occurs intermit-
tently 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 replace-
ment of good parts.
A visual check only, may not find the cause of the problems. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the “Work Flow”. Refer to AT- 6 1 , "
Work Flow" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a drive ability complaint. The cus-
tomer can supply good information about such problems, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “Diagnostic Worksheet” like the exam-
ple (AT- 5 8 , "
DIAGNOSTIC WORKSHEET" ) should be used.
Start your diagnosis by looking for “conventional” problems first. This
will help troubleshoot drive ability problems on an electronically con-
trolled engine vehicle.
Also check related Service bulletins for information.
SAT631IA
SAT632I
SEF234G
TROUBLE DIAGNOSIS — INTRODUCTION
AT-59
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Diagnostic Worksheet
1.❏ Read the Fail-safe and listen to customer complaints.AT- 5 8
2.❏ Check A/T fluidAT- 6 4
❏ Leakage (Follow specified procedure)
❏ Fluid condition
❏ Fluid level
3.❏ Perform Stall Test and Line Pressure Test.AT- 6 5
, AT- 6 8
❏ Stall test — Mark possible damaged components/others.
❏ Torque converter one-way clutch
❏ Reverse clutch
❏ Forward clutch
❏ Overrun clutch
❏ Forward one-way clutch❏ Low & reverse brake
❏ Low one-way clutch
❏ Engine
❏ Line pressure is low
❏ Clutches and brakes except high clutch and
brake band are OK
❏ Line Pressure test — Suspected parts:
4.❏ Perform all Road Test and mark required procedures.AT- 7 0
4-1. Check before engine is started.AT- 7 1
❏ O/D OFF Indicator Lamp Does Not Come On, AT-204 .
❏ SELF-DIAGNOSTIC PROCEDURE/DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION PRO-
CEDURE. — Mark detected items.
❏ PNP switch, AT- 1 0 0
.
❏ A/T fluid temperature sensor, AT- 1 0 6
.
❏ Vehicle speed sensor·A/T (Revolution sensor), AT- 11 2
.
❏ Engine speed signal, AT- 11 9
.
❏ Torque converter clutch solenoid valve, AT-148
.
❏ Line pressure solenoid valve, AT-154
.
❏ Shift solenoid valve A, AT- 1 6 1
.
❏ Shift solenoid valve B, AT- 1 6 7
.
❏ Accelerator pedal position (App) sensor, AT- 1 7 3
.
❏ Overrun clutch solenoid valve, AT- 1 7 8
.
❏ PNP & overdrive control switches, and throttle position sensor, AT- 2 3 7
.
❏ Batt/fluid temp sen (A/T fluid temperature sensor and TCM power source), AT- 1 8 4
.
❏ Vehicle speed sensor·MTR, AT-192
.
❏ CAN communication line, AT- 9 7
.
❏ Control unit (RAM), control unit (ROM), AT-198
.
❏ Control unit (EEP ROM), AT-200
.
❏ Battery
❏ Others
4-2. Check at idleAT- 7 2
❏ Engine Cannot Be Started In “P” And “N” Position, AT-206 .
❏ In “P” Position, Vehicle Moves Forward Or Backward When Pushed, AT-207
.
❏ In “N” Position, Vehicle Moves, AT- 2 0 8
.
❏ Large Shock. “N” → “R” Position, AT-209
.
❏ Vehicle Does Not Creep Backward In “R” Position, AT-210
.
❏ Vehicle Does Not Creep Forward In “D”, “2” Or “1” Position, AT- 2 1 2
.
AT-60
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TROUBLE DIAGNOSIS — INTRODUCTION
4. 4-3. Cruise testAT- 7 4
AT- 7 8Part-1
❏ Vehicle Cannot Be Started From D
1 , AT-214 .
❏ A/T Does Not Shift: D
1 → D2 Or Does Not Kickdown: D4 → D2 , AT- 2 1 7 .
❏ A/T Does Not Shift: D
2 → D3 , AT-220 .
❏ A/T Does Not Shift: D
3 → D4 , AT-222 .
❏ A/T Does Not Perform Lock-up, AT- 2 2 4
.
❏ A/T Does Not Hold Lock-up Condition, AT- 2 2 5
.
❏ Lock-up Is Not Released, AT- 2 2 7
.
❏ Engine Speed Does Not Return To Idle (Light Braking D
4 → D3 ), AT- 2 2 8 .
Part-2AT- 8 1
❏ Vehicle Does Not Start From D1 , AT-230 .
❏ A/T Does Not Shift: D
1 → D2 Or Does Not Kickdown: D4 → D2 , AT- 2 1 7 .
❏ A/T Does Not Shift: D
2 → D3 , AT-220 .
❏ A/T Does Not Shift: D
3 → D4 , AT-222 .
Part-3AT- 8 2
❏ A/T Does Not Shift: D4 → D3 When Overdrive Control Switch “ON” → “OFF”, AT- 2 3 1 .
❏ Engine Speed Does Not Return To Idle (Engine Brake In D
3 ), AT-228 .
❏ A/T Does Not Shift: D
3 → 22 , When Selector Lever “D” → “2” Position, AT-232 .
❏ Engine Speed Does Not Return To Idle (Engine Brake In 2
2 ), AT- 2 2 8 .
❏ A/T Does Not Shift: 2
2 → 11 , When Selector Lever “2” → “1” Position, AT- 2 3 3 .
❏ Vehicle Does Not Decelerate By Engine Brake, AT-235
.
❏ TCM Self-diagnosis Does Not Activate (PNP & Overdrive control switches, and throttle position sensor
circuit checks), AT-237
.
❏ SELF-DIAGNOSTIC PROCEDURE/DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION PRO-
CEDURE — Mark detected items.
❏ PNP switch, AT-100
.
❏ A/T fluid temperature sensor, AT-106
.
❏ Vehicle speed sensor·A/T (Revolution sensor), AT- 11 2
.
❏ Engine speed signal, AT- 11 9
.
❏ Torque converter clutch solenoid valve, AT- 1 4 8
.
❏ Line pressure solenoid valve, AT-154
.
❏ Shift solenoid valve A, AT-161
.
❏ Shift solenoid valve B, AT-167
.
❏ Accelerator pedal position (App) sensor, AT-173
.
❏ Overrun clutch solenoid valve, AT-178
.
❏ PNP & overdrive control switches, and throttle position sensor, AT- 2 3 7
.
❏ A/T fluid temperature sensor and TCM power source, AT-184
.
❏ Vehicle speed sensor·MTR, AT- 1 9 2
.
❏ CAN communication line, AT- 9 7
.
❏ Control unit (RAM), control unit (ROM), AT- 1 9 8
.
❏ Control unit (EEP ROM), AT- 2 0 0
.
❏ Battery
❏ Others
5.❏ For self-diagnosis NG items, inspect each component. Repair or replace the damaged parts.AT- 5 2
6.❏ Perform all Road Test and re-mark required procedures.AT- 7 0
7.❏ Perform DTC Confirmation Procedure for following MI indicating items and check out NG items.EC-53
❏ DTC (P0731) A/T 1st gear function, AT-125 .
❏ DTC (P0732) A/T 2nd gear function, AT- 1 3 0
.
❏ DTC (P0733) A/T 3rd gear function, AT-135
.
❏ DTC (P0734) A/T 4th gear function, AT-140
.
8.❏ Perform the Diagnostic Procedures for all remaining items marked NG. Repair or replace the damaged parts.
Refer to the Symptom Chart when you perform the procedures. (The chart also shows some other possible
symptoms and the component inspection orders.)AT- 8 5
9.❏ Erase DTC from TCM and ECM memories.AT- 4 2
TROUBLE DIAGNOSIS — BASIC INSPECTION
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5. Start engine and measure line pressure at idle and stall speed.
When measuring line pressure at stall speed, follow the
stall test procedure.
LINE PRESSURE
JUDGEMENT OF LINE PRESSURE TEST
SAT493G
Check lock-up hold.Line pressure kPa (bar, kg/cm2 , psi)
“D”, “2” and “1” positions “R” position
Idle 500 (5.00, 5.1, 73) 778 (7.78, 7.9, 113)
Stall 1,233 (12.33, 12.6, 179) 1,918 (19.18, 19.6, 278)
Judgement Suspected parts
At idleLine pressure is low in all positions.
Oil pump wear
Control piston damage
Pressure regulator valve or plug sticking
Spring for pressure regulator valve damaged
Fluid pressure leakage between oil strainer and pressure regulator valve
Clogged strainer
Line pressure is low in particular posi-
tion.
Fluid pressure leakage between manual valve and particular clutch
For example, line pressure is:
− Low in “R” and “1” positions, but
− Normal in “D” and “2” positions.
Therefore, fluid leakage exists at or around low and reverse brake circuit.
Refer to AT- 2 3
.
Line pressure is high.
Maladjustment of throttle position sensor
A/T fluid temperature sensor damaged
Line pressure solenoid valve sticking
Short circuit of line pressure solenoid valve circuit
Pressure modifier valve sticking
Pressure regulator valve or plug sticking
Open in dropping resistor circuit
At stall
speedLine pressure is low.
Maladjustment of throttle position sensor
Line pressure solenoid valve sticking
Short circuit of line pressure solenoid valve circuit
Pressure regulator valve or plug sticking
Pressure modifier valve sticking
Pilot valve sticking
TROUBLE DIAGNOSIS — BASIC INSPECTION
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Without CONSULT-II
Accelerator pedal position (APP) sensor can be checked by volt-
age across terminals 41 and 42 of TCM.
SCIA0710E
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
AT-85
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TROUBLE DIAGNOSIS — GENERAL DESCRIPTIONPFP:00000
Symptom ChartECS004QU
Numbers are arranged in order of inspection.
Perform inspections starting with number one and work up.
Symptom Condition Diagnostic Item Reference Page
Engine cannot start in “P” and “N”
positions.
AT- 2 0 6
ON vehicle1. Ignition switch and starterPG-2
, SC-23
2. Control cable adjustmentAT-409
3. PNP switchAT-100
Engine starts in position other than
“N” and “P” positions.
AT- 2 0 6
ON vehicle1. Control cable adjustmentAT-4092. PNP switchAT-100
Transaxle noise in “P” and “N” posi-
tions.ON vehicle1. Fluid levelAT- 6 4
2. Line pressure testAT- 6 8
3. Accelerator pedal position (APP) sensorAT-173
4. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 11 2,
AT-192
OFF vehicle5. Oil pumpAT-4436. Torque converterAT-423
Vehicle moves when changing into
“P” position, or parking gear does
not disengage when shifted out of
“P” position.
AT- 2 0 7ON vehicle 1. Control cable adjustmentAT-409
OFF vehicle 2. Parking componentsAT- 4 1 6, AT-440
Vehicle runs in “N” position.
AT- 2 0 8
ON vehicle 1. Control cable adjustmentAT-409
OFF vehicle2. Forward clutchAT-4753. Reverse clutchAT-464
4. Overrun clutchAT-475
Vehicle will not run in “R” position
(but runs in “D”, “2” and “1” posi-
tions). Clutch slips.
Very poor acceleration.
AT- 2 1 0
ON vehicle1. Control cable adjustmentAT-409
2. Stall testAT- 6 5
3. Line pressure testAT- 6 8
4. Line pressure solenoid valveAT-154
5. Control valve assemblyAT-404
Vehicle will not run in “R” position
(but runs in “D”, “2” and “1” posi-
tions). Clutch slips.
Very poor acceleration.
AT- 2 1 0
OFF vehicle6. Reverse clutchAT-464
7. High clutchAT-469
8. Forward clutchAT-475
9. Overrun clutchAT-475
10. Low & reverse brakeAT-483
Vehicle braked when shifting into
“R” position.ON vehicle1. Fluid levelAT- 6 4
2. Line pressure testAT- 6 8
3. Line pressure solenoid valveAT-154
4. Control valve assemblyAT-404
OFF vehicle5. High clutchAT-4696. Brake bandAT-497
7. Forward clutchAT-475
8. Overrun clutchAT-475
AT-86
[EURO-OBD]
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
Sharp shock in shifting from “N” to
“D” position.ON vehicle1. Engine idling rpmEC-45
2. Accelerator pedal position (APP) sensorAT-173
3. Line pressure testAT- 6 8
4. A/T fluid temperature sensorAT-184
5. Engine speed signalAT- 11 9
6. Line pressure solenoid valveAT-154
7. Control valve assemblyAT-404
8. Accumulator N-DAT-404
OFF vehicle 9. Forward clutchAT-475
Vehicle will not run in “D” and “2”
positions (but runs in “1” and “R”
positions).ON vehicle 1. Control cable adjustmentAT-409
OFF vehicle 2. Low one-way clutchAT-416, AT- 4 2 3
Vehicle will not run in “D”, “1”, “2”
positions (but runs in “R” position).
Clutch slips. Very poor acceleration.
AT- 2 1 2
ON vehicle1. Fluid levelAT- 6 4
2. Stall testAT- 6 5
3. Line pressure testAT- 6 8
4. Line pressure solenoid valveAT-154
5. Control valve assemblyAT-404
6. Accumulator N-DAT-404
Vehicle will not run in “D”, “1”, “2”
positions (but runs in “R” position).
Clutch slips. Very poor acceleration.
AT- 2 1 2
OFF vehicle7. Reverse clutchAT-464
8. High clutchAT-469
9. Forward clutchAT-475
10. Forward one-way clutchAT-416
11. Low one-way clutchAT-416, AT- 4 2 3
Clutches or brakes slip somewhat in
starting.ON vehicle1. Fluid levelAT- 6 4
2. Control cable adjustmentAT-409
3. Accelerator pedal position (APP) sensorAT-173
4. Line pressure testAT- 6 8
5. Line pressure solenoid valveAT-154
6. Control valve assemblyAT-404
7. Accumulator N-DAT-404
8. Shift solenoid valve AAT-161
9. Shift solenoid valve BAT-167
10. Overrun clutch solenoid valveAT-178
11. Torque converter clutch solenoid valveAT-148
OFF vehicle12. Forward clutchAT-475
13. Reverse clutchAT-464
14. Low & reverse brakeAT-483
15. Oil pumpAT-443
16. Torque converterAT-423
Excessive creep. ON vehicle 1. Engine idling rpm EC-45
Symptom Condition Diagnostic Item Reference Page
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
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No creep at all.
AT- 2 1 0
and AT-212
ON vehicle1. Fluid levelAT- 6 42. Line pressure testAT-387
3. Control valve assemblyAT-404
OFF vehicle4. Forward clutchAT-4755. Oil pumpAT-443
6. Torque converterAT-423
Failure to change gear from “D1 ” to
“D
2 ”.ON vehicle1. Control cable adjustmentAT-409
2. Shift solenoid valve AAT-161
3. Control valve assemblyAT-404
4. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 11 2, AT- 1 9 2
5. Accelerator pedal position (APP) sensorAT-173
OFF vehicle 6. Brake bandAT-497
Failure to change gear from “D2 ” to
“D
3 ”.ON vehicle1. Control cable adjustmentAT-409
2. Shift solenoid valve BAT-167
3. Control valve assemblyAT-404
4. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 11 2, AT- 1 9 2
5. Accelerator pedal position (APP) sensorAT-173
OFF vehicle6. High clutchAT-4697. Brake bandAT-497
Failure to change gear from “D3 ” to
“D
4 ”.ON vehicle1. PNP switchAT-100
2. Overdrive control switchAT-237
3. Shift solenoid valve AAT-161
4. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 11 2, AT- 1 9 2
5. A/T fluid temperature sensorAT-184
OFF vehicle 6. Brake bandAT-497
Too high a gear change point from
“D
1 ” to “D2 ”, from “D2 ” to “D3 ”,
from “D
3 ” to “D4 ”.
AT- 2 1 7
, AT- 2 2 0 and AT-222
ON vehicle1. Accelerator pedal position (APP) sensorAT-173
2. Vehicle speed sensor·A/T (Revolution
sensor) and vehicle speed sensor·MTRAT- 11 2, AT- 1 9 2
3. Shift solenoid valve AAT-161
4. Shift solenoid valve BAT-167
Gear change directly from “D1 ” to
“D
3 ” occurs.ON vehicle1. Fluid levelAT- 6 42. Accumulator servo releaseAT-404
OFF vehicle 3. Brake bandAT-497
Engine stops when shifting lever
into “R”, “D”, “2” and “1”.ON vehicle1. Engine idling rpm EC-45
2. Fluid levelAT- 6 4
3. Torque converter clutch solenoid valveAT-148
4. Control valve assemblyAT-404
OFF vehicle 5. Torque converterAT-423
Symptom Condition Diagnostic Item Reference Page