TROUBLE DIAGNOSIS
AT-45
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Revision: 2007 April2007 M35/M45
A/T Interlock
If there is an A/T interlock judgment malfunction, the A/T is fixed in 2nd gear to make driving possible.
NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed,
but this is not a turbine revolution sensor malfunction.
When the coupling pattern below is detected, the fail-safe action corresponding to the pattern is per-
formed.
A/T INTERLOCK COUPLING PATTERN TABLE
: NG X: OK
A/T 1st Engine Braking
When there is an A/T first gear engine brake judgment malfunction, the low coast brake solenoid is
switched OFF to avoid the engine brake operation.
Line Pressure Solenoid
The solenoid is switched OFF and the line pressure is set to the maximum hydraulic pressure to make
driving possible.
Torque Converter Clutch Solenoid
The solenoid is switched OFF to release the lock-up.
Low Coast Brake Solenoid
When a malfunction (electrical or functional) occurs, in order to make driving possible. If the solenoid is
ON, the A/T is held in 2nd gear. If the solenoid is OFF, the A/T is held in 4th gear. (Engine brake is not
applied in 1st and 2nd gear.)
Input Clutch Solenoid
If a malfunction (electrical or functional) occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Direct Clutch Solenoid
If a malfunction (electrical or functional) occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Front Brake Solenoid
If a malfunction (electrical or functional) occurs with the solenoid ON, in order to make driving possible.
The A/T is held in 5th gear. If the solenoid is OFF, the A/T is 4th gear.
High and Low Reverse Clutch Solenoid
If a (electrical or functional) malfunction occurs with the solenoid either ON or OFF, the A/T is held in 4th
gear to make driving possible.
Turbine Revolution Sensor 1 or 2
The control is the same as if there were no turbine revolution sensors, 5th gear and manual mode are pro-
hibited.
Gear positionATF pressure switch output
Fail-safe
functionClutch pressure output pattern after fail-safe func-
tion
SW3
(I/C)SW6
(HLR/
C)SW5
(D/C)SW1
(FR/B)SW2
(LC/B)I/C HLR/C D/C FR/B LC/B L/U
A/T inter-
lock cou-
pling pattern3rd – X X –Held in
2nd gearOFF OFF ON OFF OFF OFF
4th – X X –Held in
2nd gearOFF OFF ON OFF OFF OFF
5th X X – XHeld in
2nd gearOFF OFF ON OFF OFF OFF
AT-46
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
How to Perform Trouble Diagnosis for Quick and Accurate RepairNCS001K4
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, accelera-
tor pedal position 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 OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is capa-
ble of diagnosing malfunctioning parts while the ECM can store mal-
functions 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 error that occurs intermittently
rather than continuously. Most intermittent errors are caused by poor
electric connections or improper wiring. In this case, careful check-
ing of suspected circuits may help prevent the replacement of good
parts.
A visual check only may not find the cause of the errors. A road test
with CONSULT-II (or GST) or a circuit tester connected should be
performed. Follow the AT- 4 7 , "
WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such errors, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A “DIAGNOSTIC WORKSHEET” as
shown on the example (Refer to AT- 4 8
) should be used.
Start your diagnosis by looking for “conventional” errors first. This will
help troubleshoot driveability errors on an electronically controlled
engine vehicle.
Also check related Service bulletins.
SAT631IB
SAT632I
SEF234G
AT-64
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
AW D M OD E LS
At closed throttle, the accelerator opening is less than 1/8 condition. (Closed throttle position signal: OFF)
At half throttle, the accelerator opening is 4/8 of the full opening.
Symptom ChartNCS001KF
The diagnostics item numbers show the sequence for inspection. Inspect in order from item 1.
Overhaul and inspection inside the A/T only if A/T fluid condition is NG. Refer to AT- 5 3 , "A/T Fluid Condi-
tion Check" .
Engine model VQ35DE
Throttle positionVehicle speed km/h (MPH)
Lock-up ON Lock-up OFF
Closed throttle 51 - 59 (32 - 37) 48 - 56 (30 - 35)
Half throttle 188 - 196 (117 - 122) 132 - 140 (82 - 87)
No. Item Symptom Condition Diagnostic ItemReference
page
1Shift
ShockLarge shock. (“N” →
“D” position)
Refer to AT-193,
"Large Shock (“N” to
“D” Position)" .ON vehicle1. Engine idle speedEC-83
(for
VQ35DE
engine),
EC-785
(for
VK45DE
engine)
2. Engine speed signalAT- 1 2 4
3. Accelerator pedal position sensorAT- 1 3 2
4. A/T positionAT- 2 2 7
5. A/T fluid temperature sensorAT- 1 3 5
6. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2,
AT- 1 5 1
7. CAN communication lineAT- 1 0 5
8. A/T fluid level and stateAT- 5 3
9. Line pressure testAT- 5 5
10. Control valve with TCMAT- 2 3 6
OFF vehicle11. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT-17, "Cross-Sectional View (VQ35DE Models for 2WD)" , AT-18,
"Cross-Sectional View (VK45DE Models for 2WD)" o r AT-19,
"Cross-Sectional View (AWD Models)" .)AT- 3 0 1
TROUBLE DIAGNOSIS
AT-65
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Revision: 2007 April2007 M35/M45
2
Shift
ShockShock is too large
when changing D1 →
D
2 or M1 → M2 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 5 and direct clutch solenoid valveAT-176,
AT-155
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. Direct clutchAT-341
3Shock is too large
when changing D2 →
D
3 or M2 → M3 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-178,
AT-159
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. High and low reverse clutchAT-339
4Shock is too large
when changing D3 →
D
4 or M3 → M4 .ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. ATF pressure switch 3 and input clutch solenoid valveAT-174,
AT-147
4. CAN communication lineAT-105
5. Engine speed signalAT-124
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. Input clutchAT-327
No. Item Symptom Condition Diagnostic ItemReference
page
AT-66
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
5
Shift
ShockShock is too large
when changing D4 →
D
5 or M4 → M5 .ON vehicle1. Accelerator pedal position sensorAT- 1 3 2
2. A/T positionAT- 2 2 7
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2,
AT- 1 5 1
4. CAN communication lineAT- 1 0 5
5. Engine speed signalAT- 1 2 4
6. Turbine revolution sensorAT- 11 7
7. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT- 2 3 6
OFF vehicle10. Front brake (brake band)AT- 3 0 111. Input clutchAT- 3 2 7
6Shock is too large for
downshift when accel-
erator pedal is
pressed.ON vehicle1. Accelerator pedal position sensorAT- 1 3 2
2. A/T positionAT- 2 2 7
3. CAN communication lineAT- 1 0 5
4. Engine speed signalAT- 1 2 4
5. Turbine revolution sensorAT- 11 7
6. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
7. A/T fluid level and stateAT- 5 3
8. Control valve with TCMAT- 2 3 6
OFF vehicle9. Front brake (brake band)AT- 3 0 110. Input clutch AT- 3 2 7
11. High and low reverse clutchAT- 3 3 9
12. Direct clutchAT- 3 4 1
7Shock is too large for
upshift when acceler-
ator pedal is released.ON vehicle1. Accelerator pedal position sensorAT- 1 3 2
2. A/T positionAT- 2 2 7
3. Engine speed signalAT- 1 2 4
4. CAN communication lineAT- 1 0 5
5. Turbine revolution sensorAT- 11 7
6. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
7. A/T fluid level and stateAT- 5 3
8. Control valve with TCMAT- 2 3 6
OFF vehicle9. Front brake (brake band)AT- 3 0 110. Input clutch AT- 3 2 7
11. High and low reverse clutch AT- 3 3 9
12. Direct clutch AT- 3 4 1
No. Item Symptom Condition Diagnostic ItemReference
page
TROUBLE DIAGNOSIS
AT-67
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Revision: 2007 April2007 M35/M45
8
Shift
ShockShock is too large for
lock-up.ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. Engine speed signalAT-124
4. CAN communication lineAT-105
5. Turbine revolution sensorAT- 11 7
6. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
7. Torque converter clutch solenoid valveAT-126
8. A/T fluid level and stateAT- 5 3
9. Control valve with TCMAT-236
OFF vehicle 10. Torque converterAT-301
9Shock is too large
during engine brake.ON vehicle1. Accelerator pedal position sensorAT-132
2. A/T positionAT-227
3. CAN communication lineAT-105
4. A/T fluid level and stateAT- 5 3
5. Control valve with TCMAT-236
OFF vehicle6. Front brake (brake band)AT-3017. Input clutch AT-327
8. High and low reverse clutchAT-339
9. Direct clutch AT-341
10
No Up
ShiftGear does not change
from D
1 → D2 or from
M
1 → M2 .
Refer to AT-201, "
A/T
Does Not Shift: D1 →
D2" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
3. ATF pressure switch 5 and direct clutch solenoid valveAT-176,
AT-155
4. Line pressure testAT- 5 5
5. CAN communication lineAT-105
6. Control valve with TCMAT-236
OFF vehicle 7. Direct clutchAT-341
11Gear does not change
from D
2 → D3 or from
M
2 → M3 .
Refer to AT-203, "
A/T
Does Not Shift: D2 →
D3" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-178,
AT-159
4. Line pressure testAT- 5 5
5. CAN communication lineAT-105
6. Control valve with TCMAT-236
OFF vehicle 7. High and low reverse clutchAT-339
No. Item Symptom Condition Diagnostic ItemReference
page
AT-68
TROUBLE DIAGNOSIS
Revision: 2007 April2007 M35/M45
12
No Up
ShiftGear does not change
from D
3 → D4 or from
M
3 → M4 .
Refer to AT-205, "
A/T
Does Not Shift: D3 →
D4" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
3. ATF pressure switch 3 and input clutch solenoid valveAT- 1 7 4,
AT- 1 4 7
4. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2,
AT- 1 5 1
5. Line pressure testAT- 5 5
6. CAN communication lineAT- 1 0 5
7. Control valve with TCMAT- 2 3 6
OFF vehicle 8. Input clutchAT- 3 2 7
13Gear does not change
from D
4 → D5 or from
M
4 → M5 .
Refer to AT-207, "
A/T
Does Not Shift: D4 →
D5" .ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2,
AT- 1 5 1
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 7 6,
AT- 1 5 5
5. Turbine revolution sensorAT- 11 7
6. Line pressure testAT- 5 5
7. CAN communication lineAT- 1 0 5
8. Control valve with TCMAT- 2 3 6
OFF vehicle9. Front brake (brake band)AT- 3 0 110. Input clutchAT- 3 2 7
14No Down
ShiftIn “D” or “M” position,
does not downshift to
4th gear.ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT- 1 4 0
3. ATF pressure switch 1 and front brake solenoid valveAT- 1 7 2
,
AT- 1 5 1
4. ATF pressure switch 5 and direct clutch solenoid valveAT- 1 7 6,
AT- 1 5 5
5. CAN communication lineAT- 1 0 5
6. Line pressure testAT- 5 5
7. Control valve with TCMAT- 2 3 6
OFF vehicle8. Front brake (brake band)AT- 3 0 19. Input clutchAT- 3 2 7
No. Item Symptom Condition Diagnostic ItemReference
page
TROUBLE DIAGNOSIS
AT-69
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Revision: 2007 April2007 M35/M4515
No Down
ShiftIn “D” or “M” position,
does not downshift to
3rd gear.ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
3. ATF pressure switch 3 and input clutch solenoid valveAT-174,
AT-147
4. ATF pressure switch 1 and front brake solenoid valveAT-172,
AT-151
5. CAN communication lineAT-105
6. Line pressure testAT- 5 5
7. Control valve with TCMAT-236
OFF vehicle 8. Input clutchAT-327
16In “D” or “M” position,
does not downshift to
2nd gear.ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
3. ATF pressure switch 6, high and low reverse clutch sole-
noid valveAT-178
,
AT-159
4. CAN communication lineAT-105
5. Line pressure testAT- 5 5
6. Control valve with TCMAT-236
OFF vehicle 7. High and low reverse clutchAT-339
17In “D” or “M” position,
does not downshift to
1st gear.ON vehicle1. A/T fluid level and stateAT- 5 3
2. Vehicle speed sensor·A/T and vehicle speed sensor·MTRAT- 11 9,
AT-140
3. ATF pressure switch 5 and direct clutch solenoid valveAT-176,
AT-155
4. CAN communication lineAT-105
5. Line pressure testAT- 5 5
6. Control valve with TCMAT-236
OFF vehicle 7. Direct clutchAT-341
No. Item Symptom Condition Diagnostic ItemReference
page