TROUBLE DIAGNOSIS
AT-47
< SERVICE INFORMATION >
D
E
F
G
H
I
J
K
L
MA
B
AT
N
O
P
Circuit DiagramINFOID:0000000001703181
7. Revolution sensor 8. Dropping resistor 9. TCM
10. Overdrive control switch
BCWA0647E
AT-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Line Pressure
Judgement of Line Pressure Test
Road TestINFOID:0000000001703183
DESCRIPTION
• The purpose of the test is to determine overall performance of A/T
and analyze causes of malfunctions.
• The road test consists of the following three parts:
1. Check before engine is started. Refer to AT- 5 3
.
2. Check at idle. Refer to AT- 5 3
.
3. Cruise test
• Inspection all the item from Part 1 to Part 3. Refer to AT- 5 5
,
AT- 5 8
and AT- 5 9 .
Engine speedLine pressure [kPa (kg/cm
2 , psi)]
D, 2nd and 1st positions R position
Idle speed 500 (5.1, 73) 778 (7.9, 113)
Stall speed 1,173 (12.0, 170) 1,825 (18.6, 265)
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- 1 9 , "
Shift Mechanism".
Line pressure is high. • Accelerator pedal position signal malfunction
• 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. • Accelerator pedal position signal malfunction
• 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
SAT786A
AT-62
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Perform inspections starting with number one and work up.
Items Symptom Condition Diagnostic item Reference page
No Lock-up Engage-
ment/TCC InoperativeTorque converter is
not locked up.ON vehicle1. Accelerator pedal position sensorEC-493
2. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
3. Engine speed signalAT- 1 0 1
4. A/T fluid temperature sensorAT- 9 1
5. Line pressure testAT- 4 8
6. Torque converter clutch solenoid valveAT- 11 9
7. Control valve assemblyAT- 2 1 6
OFF vehicle 8. Torque converterAT- 2 4 0
Torque converter
clutch piston slip.ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Torque converter clutch solenoid valveAT- 11 9
5. Line pressure solenoid valveAT- 1 2 9
6. Control valve assemblyAT- 2 1 6
OFF vehicle 7. Torque converterAT- 2 4 0
Lock-up point is ex-
tremely high or low.ON vehicle1. Accelerator pedal position sensorEC-4932. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
3. Torque converter clutch solenoid valveAT- 11 9
4. Control valve assemblyAT- 2 1 6
Shift ShockSharp shock in shift-
ing from “N” to “D” po-
sition.ON vehicle1. Engine idling speedEC-73
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. A/T fluid temperature sensorAT- 9 1
5. Engine speed signalAT- 1 0 1
6. Line pressure solenoid valveAT- 1 2 9
7. Control valve assemblyAT- 2 1 6
8. Accumulator N-DAT- 2 1 6
OFF vehicle 9. Forward clutchAT- 2 8 8
Too sharp a shock in
changing from D
1 to
D
2 .ON vehicle1. Accelerator pedal position sensorEC-493
2. Line pressure testAT- 4 8
3. Accumulator servo releaseAT- 2 1 6
4. Control valve assemblyAT- 2 1 6
5. A/T fluid temperature sensorAT- 9 1
OFF vehicle 6. Brake bandAT- 3 0 7
TROUBLE DIAGNOSIS
AT-63
< SERVICE INFORMATION >
D
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AT
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Shift ShockToo sharp a shock in
changing from D
2 to
D
3 .ON vehicle1. Accelerator pedal position sensorEC-493
2. Line pressure testAT- 4 8
3. Control valve assemblyAT- 2 1 6
OFF vehicle4. High clutchAT- 2 8 45. Brake bandAT- 3 0 7
Too sharp a shock in
changing from D
3 to
D
4 .ON vehicle1. Accelerator pedal position sensorEC-493
2. Line pressure testAT- 4 8
3. Control valve assemblyAT- 2 1 6
OFF vehicle4. Brake bandAT- 3 0 75. Overrun clutchAT- 2 8 8
6. Forward one-way clutchAT- 2 9 9
Gear change shock
during deceleration by
releasing accelerator
pedal.ON vehicle1. Accelerator pedal position sensorEC-4932. Line pressure testAT- 4 8
3. Overrun clutch solenoid valveAT- 1 4 4
4. Control valve assemblyAT- 2 1 6
Large shock in chang-
ing from 1
2 to 11 in
“1” position.ON vehicle 1. Control valve assemblyAT- 2 1 6OFF vehicle 2. Low & reverse brakeAT- 2 9 5
Improper Shift TimingToo high a gear
change point from D
1
to D
2 , from D2 to D3 ,
from D
3 to D4 .ON vehicle1. Accelerator pedal position sensorEC-493
2. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
3. Shift solenoid valve AAT- 1 3 4
4. Shift solenoid valve BAT- 1 3 9
Gear change directly
from D
1 to D3 occurs.ON vehicle1. A/T fluid levelMA-222. Accumulator servo releaseAT- 2 1 6
OFF vehicle 3. Brake bandAT- 3 0 7
Too high a change
point from D
4 to D3 ,
from D
3 to D 2 , from
D
2 to D1 .ON vehicle1. Accelerator pedal position sensorEC-493
2. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
Kickdown does not
operate when de-
pressing accelerator
pedal in D
4 within
kickdown vehicle
speed.ON vehicle1. Accelerator pedal position sensorEC-493
2. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
3. Shift solenoid valve AAT- 1 3 4
4. Shift solenoid valve BAT- 1 3 9
Kickdown operates or
engine overruns when
depressing accelera-
tor pedal in D
4 be-
yond kickdown
vehicle speed limit.ON vehicle1. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6
, AT- 1 4 9
2. Accelerator pedal position sensorEC-493
3. Shift solenoid valve AAT- 1 3 4
4. Shift solenoid valve BAT- 1 3 9
Gear change from 22
to 2
3 in “2” position.ON vehicle1. PNP switch adjustmentAT- 2 1 92. Control cable adjustmentAT- 2 0 7
Gear change from 11
to 1
2 in “1” position.ON vehicle1. PNP switch adjustmentAT- 2 1 92. Control cable adjustmentAT- 2 0 7
Items Symptom Condition Diagnostic item Reference page
AT-64
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
No Down ShiftFailure to change
gear from D
4 to D3 .ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Overrun clutch solenoid valveAT- 1 4 4
4. Shift solenoid valve A AT- 1 3 4
5. Line pressure solenoid valveAT- 1 2 9
6. Control valve assemblyAT- 2 1 6
OFF vehicle7. Brake bandAT- 3 0 78. Overrun clutchAT- 2 8 8
Failure to change
gear from D
3 to D2 or
from D
4 to D2 .ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Shift solenoid valve AAT- 1 3 4
4. Shift solenoid valve BAT- 1 3 9
5. Control valve assemblyAT- 2 1 6
OFF vehicle6. High clutchAT- 2 8 47. Brake bandAT- 3 0 7
Failure to change
gear from D
2 to D1 or
from D
3 to D1 .ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Shift solenoid valve AAT- 1 3 4
4. Shift solenoid valve BAT- 1 3 9
5. Control valve assemblyAT- 2 1 6
OFF vehicle6. Low one-way clutchAT- 2 4 07. High clutchAT- 2 8 4
8. Brake bandAT- 3 0 7
Failure to change
from D
3 to 22 when
shifting selector lever
into “2” position.
AT- 1 9 4ON vehicle1. Accelerator pedal position sensorEC-4932. Shift solenoid valve BAT- 1 3 9
3. Control valve assembly AT- 2 1 6
4. Control cable adjustmentAT- 2 0 7
OFF vehicle 5. Brake bandAT- 3 0 7
Does not change from
1
2 to 11 in 1st posi-
tion.ON vehicle1. PNP switch adjustmentAT- 2 1 9
2. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
3. Shift solenoid valve AAT- 1 3 4
4. Control valve assemblyAT- 2 1 6
5. Overrun clutch solenoid valveAT- 1 4 4
OFF vehicle6. Overrun clutchAT- 2 8 87. Low & reverse brakeAT- 2 9 5
Items Symptom Condition Diagnostic item Reference page
TROUBLE DIAGNOSIS
AT-65
< SERVICE INFORMATION >
D
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AT
N
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No Up ShiftFailure to change
gear from D
1 to D2 .ON vehicle1. Control cable adjustmentAT- 2 0 7
2. Shift solenoid valve AAT- 1 3 4
3. Control valve assemblyAT- 2 1 6
4. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
5. Accelerator pedal position sensorEC-493
OFF vehicle 6. Brake bandAT- 3 0 7
Failure to change
gear from D
2 to D3 .ON vehicle1. Control cable adjustmentAT- 2 0 7
2. Shift solenoid valve BAT- 1 3 9
3. Control valve assemblyAT- 2 1 6
4. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
5. Accelerator pedal position sensorEC-493
OFF vehicle6. High clutchAT- 2 8 47. Brake bandAT- 3 0 7
Failure to change
gear from D
3 to D4 .ON vehicle 1. PNP switch adjustmentAT- 2 1 9
2. Overdrive control switchAT- 1 6 7
3. Control cable adjustmentAT- 2 0 7
4. Shift solenoid valve AAT- 1 3 4
5. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
6. A/T fluid temperature sensorAT- 9 1
OFF vehicle 7. Brake band AT- 3 0 7
A/T does not shift to
D
4 when driving with
OD ON. (OD OFF in-
dicator lamp is off.)ON vehicle1. Accelerator pedal position sensorEC-493
2. PNP switch adjustmentAT- 2 1 9
3. Overdrive control switchAT- 1 6 7
4. Vehicle speed sensor·A/T (Revolution sensor)
and vehicle speed sensor·MTRAT- 9 6, AT- 1 4 9
5. Shift solenoid valve AAT- 1 3 4
6. Overrun clutch solenoid valveAT- 1 4 4
7. Control valve assemblyAT- 2 1 6
8. A/T fluid temperature sensorAT- 9 1
9. Line pressure solenoid valveAT- 1 2 9
OFF vehicle10. Brake bandAT- 3 0 711. Overrun clutchAT- 2 8 8
Items Symptom Condition Diagnostic item Reference page
AT-66
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Slips/Will Not EngageVehicle will not run in
“R” position (but runs
in “D”, “2” and “1” po-
sitions). Clutch slips.
Very poor accelera-
tion.ON vehicle1. Control cable adjustmentAT- 2 0 7
2. Stall testAT- 4 8
3. Line pressure testAT- 4 8
4. Line pressure solenoid valveAT- 1 2 9
5. Control valve assemblyAT- 2 1 6
OFF vehicle6. Reverse clutchAT- 2 7 9
7. High clutchAT- 2 8 4
8. Forward clutchAT- 2 8 8
9. Overrun clutchAT- 2 8 8
10. Low & reverse brakeAT- 2 9 5
Vehicle will not run in
“D” and “2” positions
(but runs in “1” and
“R” positions).ON vehicle 1. Control cable adjustmentAT- 2 0 7
OFF vehicle 2. Low one-way clutchAT- 2 4 0
Vehicle will not run in
“D”, “1”, “2” positions
(but runs in R posi-
tion). Clutch slips.
Very poor accelera-
tion.ON vehicle1. A/T fluid levelMA-22
2. Stall testAT- 4 8
3. Line pressure testAT- 4 8
4. Line pressure solenoid valveAT- 1 2 9
5. Control valve assemblyAT- 2 1 6
6. Accumulator N-DAT- 2 1 6
OFF vehicle7. Reverse clutchAT- 2 7 9
8. High clutchAT- 2 8 4
9. Forward clutchAT- 2 8 8
10. Forward one-way clutchAT- 2 9 9
11. Low one-way clutchAT- 2 4 0
Clutches or brakes
slip somewhat in start-
ing.ON vehicle1. A/T fluid levelMA-22
2. Control cable adjustmentAT- 2 0 7
3. Accelerator pedal position sensorEC-493
4. Line pressure testAT- 4 8
5. Line pressure solenoid valveAT- 1 2 9
6. Control valve assemblyAT- 2 1 6
7. Accumulator N-DAT- 2 1 6
OFF vehicle8. Forward clutchAT- 2 8 8
9. Reverse clutchAT- 2 7 9
10. Low & reverse brakeAT- 2 9 5
11 . O i l p u m pAT- 2 6 0
12. Torque converterAT- 2 4 0
Items Symptom Condition Diagnostic item Reference page
TROUBLE DIAGNOSIS
AT-67
< SERVICE INFORMATION >
D
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F
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K
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MA
B
AT
N
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Slips/Will Not EngageNo creep at all.
AT- 1 8 1
, AT- 1 8 2
ON vehicle1. A/T fluid levelMA-222. Line pressure testAT- 4 8
3. Control valve assemblyAT- 2 1 6
OFF vehicle4. Forward clutchAT- 2 8 85. Oil pumpAT- 2 6 0
6. Torque converterAT- 2 4 0
Almost no shock or
clutches slipping in
change from D
1 to D2
.ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Accumulator servo releaseAT- 2 1 6
5. Control valve assemblyAT- 2 1 6
OFF vehicle 6. Brake bandAT- 3 0 7
Almost no shock or
slipping in changing
from D
2 to D3 .ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Control valve assemblyAT- 2 1 6
OFF vehicle5. High clutchAT- 2 8 46. Forward clutchAT- 2 8 8
Almost no shock or
slipping in changing
from D
3 to D4 .ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Control valve assemblyAT- 2 1 6
OFF vehicle 5. Brake bandAT- 3 0 7
Races extremely fast
or slips in changing
from D
4 to D3 when
depressing accelera-
tor pedal.ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Line pressure solenoid valveAT- 1 2 9
5. Shift solenoid valve AAT- 1 3 4
6. Control valve assemblyAT- 2 1 6
OFF vehicle7. Brake bandAT- 3 0 78. Forward clutchAT- 2 8 8
Races extremely fast
or slips in changing
from D
4 to D2 when
depressing accelera-
tor pedal.ON vehicle1. A/T fluid levelMA-22
2. Accelerator pedal position sensorEC-493
3. Line pressure testAT- 4 8
4. Line pressure solenoid valveAT- 1 2 9
5. Shift solenoid valve AAT- 1 3 4
6. Shift solenoid valve BAT- 1 3 9
7. Control valve assemblyAT- 2 1 6
OFF vehicle8. Brake bandAT- 3 0 79. Forward clutchAT- 2 8 8
Items Symptom Condition Diagnostic item Reference page