Page 425 of 656

7B1-16 AUTOMATIC TRANSMISSION (4 A/T)
GEAR SHIFT
Trouble Diagnosis Table 3
TRANSMISSION FLUID
RUNNING CONDITION
Condition Possible Cause Correction
Poor 1–2 shift, exces-
sive slippageRegulator valve sticking Replace.
1–2 shift valve sticking Replace.
Shift solenoid valve-B sticking Replace.
Intermediate coast modulator valve sticking Replace.
Poor 2–3 shift, exces-
sive slippage2–3 shift valve sticking Replace.
Shift solenoid valve-A sticking Replace.
Poor start or surging
in “D” rangeRegulator valve sticking Replace.
Poor 3-4 shift, exces-
sive slippage3–4 shift valve sticking Replace.
Shift solenoid valve-B sticking Replace.
Excessive shock on
1–2 shiftRegulator valve sticking Replace.
Faulty accumulator, second brake piston Replace.
Excessive shock on
2–3 shiftRegulator valve sticking Replace.
Faulty accumulator, direct clutch piston Replace.
Excessive shock on
3–4 shiftRegulator valve sticking Replace.
Non operate lock-up
systemTCC (Lock-up) control valve sticking Replace.
Solenoid valve No.2 (TCC solenoid valve) stick-
ingReplace.
Condition Possible Cause Correction
Low fluid pressureLeakage from oil pressure circuit Overhaul.
Condition Possible Cause Correction
Unable to run in all
rangeWear in oil pump Replace.
Seizure in oil pump Replace.
Fluid pressure leakage to over drive clutch due
to wear of oil pump bushingReplace.
Faulty in torque converter Replace.
Poor 1st speed run-
ning or excessive slip-
page in “D” or “2”Fluid pressure leakage from forward clutch due
to wear or breakage of O/D case seal ringReplace.
Overdrive clutch slipping Replace.
Unable to run or
excessive slippage in
“L” rangeFluid pressure leakage of forward clutch due to
wear or breakage of O/D case seal ringReplace.
Reverse brake disc slipping Replace.
Broken brake piston O-ring Replace.
Unable to run or
excessive slippage in
“R” rangeFluid pressure leakage to direct clutch due to
wear or breakage of center support seal ringReplace.
Worn direct clutch Replace.
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AUTOMATIC TRANSMISSION (4 A/T) 7B1-17
GEAR SHIFT
ABNORMAL NOISE
Scan Tool Data
Refer to Section 6-1.
Inspection of PCM and Its Circuit
Refer to Section 6-1.
Wire Harness and Connectors
Refer to Section 6-1.Condition Possible Cause Correction
Poor 1–2 shift, exces-
sive slippageFluid pressure leakage to overdrive clutch due
to wear or breakage of O/D case seal ringReplace.
Faulty second brake Replace.
Broken O-ring of second brake piston Replace.
Faulty second coast brake (in “2” range) Replace.
Poor 2–3 shift, exces-
sive slippageFluid pressure leakage to overdrive clutch due
to wear or breakage of O/D case seal ringReplace.
Worn direct clutch bushing Replace.
Direct clutch slipping Replace.
Foreign material caught in direct clutch piston
check ballReplace.
Poor start or surging
in “D” rangeFluid pressure leakage of forward clutch due to
wear or breakage of O/D case seal ringReplace.
Malfunction of forward clutch Replace.
Poor 3–4 shift, exces-
sive slippageFaulty overdrive brake Replace.
Faulty overdrive clutch Replace.
Poor start or juddering
in “R” rangeFluid pressure leakage of direct clutch due to
wear or breakage of oil center support seal ringReplace.
Worn direct clutch Replace.
Excessive shock on
1– 2 shiftFaulty one-way clutch Replace.
Non operate lock-up
systemFaulty torque converter Replace.
Condition Possible Cause Correction
Abnormal noise in “P”
or “N” rangeWorn oil pump Replace.
Page 427 of 656

7B1-18 AUTOMATIC TRANSMISSION (4 A/T)
Table A-1 : No TCC Lock-Up Occurs
SYSTEM DESCRIPTION
PCM turns TCC solenoid OFF under any of the following conditions.
•Brake pedal switch : ON
•4WD LOW switch : ON
•Cruise control module : TCC OFF command signal is output (if equipped).
•ECT : ECT < 30 °C (86 °F)
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 person, a driver and tester, on a level road.
Step Action Yes No
1Was “AUTOMATIC TRANSMISSION DIAG-
NOSTIC FLOW TABLE” performed?Go to Step 2. Go to “AUTOMATIC
TRANSMISSION DIAG-
NOSTIC FLOW TABLE” in
this section.
2 ECT check :
1) Warm up engine to normal operating tem-
perature.
2) Check ECT using scan tool.
Is ECT more than 30 °C (86 °F)?Go to Step 3. Faulty ECT sensor, its cir-
cuit or engine cooling sys-
tem.
If OK, substitute a known-
good PCM and recheck.
3 Perform running test under the following condi-
tions and check voltage between C51-1-8 termi-
nal of PCM coupler and ground.
•Normal mode in “D” range.
•Transfer “2H” position.
•Cruise control is not operated (if equipped).
•Brake pedal released.
•Drive vehicle with TCC ON condition refer-
ring to “TCC LOCK-UP DIAGRAM” in this
section.
Is it battery voltage?Faulty TCC solenoid
valve, its circuit or trans-
mission.Go to Step 4.
4 Brake switch signal inspection :
With ignition switch ON, check voltage between
E61-34 terminal of PCM coupler terminal and
ground.
Brake switch specification
Brake pedal released : 0 V
Brake pedal depressed : Battery voltage
Is the result as specified?Go to Step 5. Faulty brake pedal switch
or its circuit.
If OK, substitute a known-
good PCM and recheck.
Page 428 of 656
AUTOMATIC TRANSMISSION (4 A/T) 7B1-19
5“4WD LOW” switch signal inspection :
With ignition switch ON, check voltage between
C51-1-26 terminal of PCM coupler and ground.
“4WD LOW” switch specification
Transfer gear position “4L” or “N” : 0 V
Transfer gear position “4H” or “2H” :
Battery voltage
Is the result as specified?Go to Step 6. Faulty “4WD LOW” switch
or its circuit.
If OK, substitute a known-
good PCM and recheck.
6 Is vehicle equipped with cruise control system? Go to Step 7. Substitute a know-good
PCM and recheck.
7 Cruise control signal inspection :
With ignition switch ON, check voltage between
E61-35 terminal of PCM coupler and ground.
Is it battery voltage?Substitute a known-good
PCM and recheck.Faulty cruise control mod-
ule or its circuit.
If OK, substitute a known-
good PCM and recheck. Step Action Yes No
Page 429 of 656

7B1-20 AUTOMATIC TRANSMISSION (4 A/T)
Table A-2 : No Gear Shift to O/D
SYSTEM DESCRIPTION
PCM does not shift to O/D gear under any of the following conditions.
•O/D off switch : ON
•4WD LOW switch : ON
•Cruise control module : O/D OFF command signal is output (if equipped).
•ECT : ECT < 30 °C (86 °F)
TROUBLESHOOTING
WARNING:
When performing a road test, select a place where there is no traffic or possibility of a traffic acci-
dent and very careful during testing to avoid occurrence of an accident.
Road test should be carried out with 2 person, a driver and tester, on a level road.
Step Action Yes No
1Was “AUTOMATIC TRANSMISSION DIAG-
NOSTIC FLOW TABLE” performed?Go to Step 2. Go to “AUTOMATIC
TRANSMISSION DIAG-
NOSTIC FLOW TABLE” in
this section.
2 ECT check :
1) Warm up engine to normal operating tem-
perature.
2) Check ECT using scan tool.
Is ECT more than 30 °C (86 °F)?Go to Step 3. Faulty ECT sensor, its cir-
cuit or engine cooling sys-
tem.
If OK, substitute a known-
good PCM and recheck.
3 Perform running test under the following condi-
tions and check voltage between C51-1-2 termi-
nal of PCM coupler and ground, C51-1-1
terminal of PCM coupler and ground.
•O/D off switch OFF (“O/D OFF” lamp OFF).
•Normal mode in “D” range.
•Transfer “2H” position.
•Cruise control is not operated (if equipped).
•Drive vehicle with 4th gear condition refer-
ring to “Gear shift diagram” in this section.
Is each voltage about 0 V?Faulty shift solenoid valve,
its circuit or transmission“GRN” wire or “GRN/
RED” wire shorted to
power circuit.
If OK, go to Step 4.
4 O/D off switch signal inspection :
With ignition switch ON, check voltage between
E61-33 terminal of PCM coupler and ground.
“O/D” cut switch specification
“O/D” cut switch OFF : Battery voltage
“O/D” cut switch ON : 0 V
Is the result as specified?Go to Step 5. Faulty O/D off switch or its
circuit.
If OK, substitute a known-
good PCM and recheck.
Page 430 of 656
AUTOMATIC TRANSMISSION (4 A/T) 7B1-21
5“4WD LOW” switch signal inspection :
With ignition switch ON, check voltage between
C51-1-26 terminal of PCM coupler and ground.
“4WD LOW” switch specification
Transfer gear position “4L” or “N” : 0 V
Transfer gear position “4H” or “2H” :
Battery voltage
Is the result as specified?Go to Step 6. Faulty “4WD LOW” switch
or its circuit.
If OK, substitute a known-
good PCM and recheck.
6 Is vehicle equipped with cruise control system? Go to Step 7. Substitute a known-good
PCM and recheck.
7 Cruise control signal inspection :
With ignition switch ON, check voltage between
E61-35 terminal of PCM coupler and ground.
Is it battery voltage?Substitute a known-good
PCM and recheck.Faulty cruise control mod-
ule or its circuit.
If OK, substitute a known-
good PCM and recheck. Step Action Yes No
Page 431 of 656
7B1-22 AUTOMATIC TRANSMISSION (4 A/T)
Table B-1 : “O/D OFF” Light Circuit Check (“O/D OFF” Light Doesn’t Light at
Ignition Switch ON But Engine Starts Up)
WIRING DIAGRAM
TROUBLESHOOTING
1. PCM 4. P/N change switch
2. Fuse 5. J/C
3. O/D off switch 6. J/C
Step Action Yes No
1“O/D OFF” light circuit check:
1) With ignition switch OFF, disconnect cou-
plers from PCM.
2) Using service wire, connect E61-20 termi-
nal of disconnected PCM coupler and
ground.
Does “O/D OFF” light turn ON at ignition switch
ON?Poor E61-20 terminal con-
nection.
If OK, substitute a know-
good PCM and recheck.Bulb burned out or faulty
“WHT/BLK”, “BLK/WHT”
wire.
Page 432 of 656

AUTOMATIC TRANSMISSION (4 A/T) 7B1-23
Table B-2 : “O/D OFF” Light Circuit Check (“O/D OFF” Light Comes ON
Steadily)
WIRING DIAGRAM
Refer to “TABLE B-1” in this section.
TROUBLESHOOTING
[A] for Step 1/[B] for Step 4Step Action Yes No
1 Check O/D off switch status.
Press O/D off switch button (1).
Does “O/D OFF” lamp come ON steadily?Go to Step 2. System is OK.
2 Check lamp circuit for short.
1) Turn ignition switch OFF and disconnect
PCM connectors.
2) Turn ignition switch ON.
Does “O/D OFF” lamp come ON steadily?“WHT/BLK” circuit
shorted to ground.Go to Step 3.
3 Check O/D off switch circuit.
1) Check resistance between terminal E61-33
of disconnected PCM connector and body
ground with O/D off switch button (1)
released.
Is continuity indicated?Go to Step 4. Check PCM ground circuit
for open.
If ground circuit is OK,
substitute a known-good
PCM and recheck.
4 Check O/D off switch for operation.
1) Remove console box.
2) Disconnect O/D off switch connector.
3) Check continuity between switch terminals
under each condition below.
O/D switch operation
With O/D off switch button (1) released :
No continuity
With O/D off switch button (1) pressed :
Continuity
Is check result satisfactory?“YEL/RED” circuit shorted
to ground.Replace O/D off switch.