2004 INFINITI QX56 engine

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-191
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Revision: August 20072004 QX56
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
AT CHECK Indicator Lamp Does Not Come OnUCS002II
SYMPTOM:
AT CHECK indicator lamp does not come on for about 2 seconds when turning ignition switch to
“ON”.
DIAGNOSTIC PROCEDURE
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT - 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is any malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK TCM POWER SOURCE
1. Disconnect A/T assembly harness connector.
2. Turn ignition switch “ON”. (Do not start engine.)
3. Check voltage between A/T assembly harness connector (vehi-
cle side) and ground. Refer to AT- 5 2 , "
Wiring Diagram — AT —"
.
4. Turn ignition switch “OFF”.
5. Check voltage between A/T assembly harness connector (vehi-
cle side) and ground. Refer to AT- 5 2 , "
Wiring Diagram — AT —"
.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

Harness for short or open between battery and A/T assembly harnhess connector terminals 1, 2

Harness for short or open between ignition switch and TCM connector terminal 6

10A fuse (No. 3, located in the fuse block)

10A fuse (No. 49, located in the IPDM E/R)

Ignition switch, Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
Item Connector No.Te r m i n a l N o .
(Wire color)Vo ltag e
TCM F91 (P) - Ground
Battery voltage 2 (P) - Ground
6 (Y/R) - Ground
SCIA2105E
Item Connector No.Te r m i n a l N o .
(Wire color)Voltage
TCM F91 (P) - Ground
Battery voltage
2 (P) - Ground
6 (Y/R) - Ground 0V
SCIA2104E

AT-192
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
4. CHECK TCM GROUND CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect the A/T assembly harness connector.
3. Check the continuity between A/T assembly harness connector
(vehicle side) 5 (B), 10 (B) and ground. Refer to AT - 5 2 , "
Wiring
Diagram — AT —" .
4. If OK, check the harness for short-circuit to ground or the power
source.
OK or NG
OK >> GO TO 5.
NG >> Repair the open or short circuit in the harness or con-
nector.
5. CHECK AT CHECK INDICATOR LAMP CIRCUIT
1. Turn ignition switch “OFF”.
2. Check the combination meter.
Refer to DI-17, "
How to Proceed With Trouble Diagnosis" .
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Engine Cannot Be Started In “P” or “N” PositionUCS002IJ
SYMPTOM:

Engine cannot be started with selector lever in “P” or “N” position.

Engine can be started with selector lever in “D”or “R” position.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSIS RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnosis results indicate PNP switch?
YES >> Check the malfunctioning system. Refer to AT-109, "DTC P0705 PARK/NEUTRAL POSITION
SWITCH" .
NO >> GO TO 2.
2. CHECK CONTROL CABLE
Check the control cable.

Refer to AT-234, "Checking of A/T Position" .
OK or NG
OK >> GO TO 3.
NG >> Adjust control cable. Refer to AT-234, "
Adjustment of A/
T Position" .
SCIA2106E
LCIA0324E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-195
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Revision: August 20072004 QX56
5. CHECK SYMPTOM
Check again. Refer to AT- 6 2 , "
Check at Idle" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 6.
6. PERFORM TCM INSPECTION
1. Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Val-
ues" .
2. If NG, recheck A/T assembly harness connector terminals for damage or loose connection with harness
connector.
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Large Shock (“N” to “D” Position)UCS002IM
SYMPTOM:
A noticeable shock occurs when the selector lever is shifted from the “N” to “D” position.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate A/T fluid temperature sensor, engine speed signal, accelerator pedal
position sensor, ATF pressure switch 1, front brake solenoid valve, CAN communication line?
YES >> Check the malfunctioning system. Refer to AT-131, "DTC P1710 A/T FLUID TEMPERATURE
SENSOR CIRCUIT" , AT-115, "DTC P0725 ENGINE SPEED SIGNAL" ., AT- 1 2 9 , "DTC P1705
THROTTLE POSITION SENSOR" , AT-175, "DTC P1841 ATF PRESSURE SWITCH 1" , AT-
151, "DTC P1757 FRONT BRAKE SOLENOID VALVE" , AT- 1 0 3 , "DTC U1000 CAN COMMUNI-
CATION LINE" .
NO >> GO TO 2.
2. ENGINE IDLE SPEED
Check the engine idle speed. Refer to EC-32, "
Idle Speed and Ignition Timing Check" .
OK or NG
OK >> GO TO 3.
NG >> Repair.
3. CHECK CONTROL CABLE
Check the control cable.

Refer to AT- 2 3 4 , "Checking of A/T Position" .
OK or NG
OK >> GO TO 4.
NG >> Adjust control cable. Refer to AT-234, "
Adjustment of A/
T Position" .
LCIA0324E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-199
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Revision: August 20072004 QX56
5. DETECT MALFUNCTIONING ITEM
1. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
2. Check the following items:
–Reverse brake. Refer to AT-273, "Disassembly" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
6. CHECK LINE PRESSURE
Check the line pressure with the engine idling. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 9.
NG - 1 >> Line pressure high. GO TO 7.
NG - 2 >> Line pressure low. GO TO 8.
7. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
8. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.
SAT4 9 4G

AT-204
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
3. CHECK ACCELERATOR PEDAL POSITION (APP) SENSOR
Check accelerator pedal position (APP) sensor. Refer to AT- 1 2 9 , "
DTC P1705 THROTTLE POSITION SEN-
SOR"
OK or NG
OK >> GO TO 4.
NG >> Repair or replace accelerator pedal position (APP) sensor.
4. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT-13, "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 5.
NG >> Refill ATF.
5. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT- 5 9 , "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 8.
NG - 1 >> Line pressure high. GO TO 6.
NG - 2 >> Line pressure low. GO TO 7.
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT- 2 4 1 , "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT-273, "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
SAT6 3 8A
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AT-206
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
12. DETECT MALFUNCTIONING ITEM

Check the malfunction items. If any items are damaged, repair or replace damaged parts. Refer to AT-68,
"Symptom Chart" (Symptom No.23).
OK or NG
OK >> GO TO 10.
NG >> Repair or replace damaged parts.
A/T Does Not Shift: D1 → D2UCS002IQ
SYMPTOM:
The vehicle does not shift-up from the D1 to D2 gear at the specified speed.
DIAGNOSTIC PROCEDURE
1. CONFIRM THE SYMPTOM
Check if vehicle creeps forward in “D” position and vehicle can be started from D
1.
OK or NG
OK >> GO TO 2.
NG >> Refer to AT-201, "
Vehicle Does Not Creep Forward In “D” Position" , AT - 2 0 3 , "Vehicle Cannot Be
Started From D1" .
2. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnostic results indicate ATF pressure switch 5, direct clutch solenoid valve, accelerator pedal
position sensor, vehicle speed sensor A/T (revolution sensor) and vehicle speed sensor MTR?
YES >> Check the malfunctioning system. Refer to AT-181, "DTC P1845 ATF PRESSURE SWITCH 5" ,
AT-157, "
DTC P1762 DIRECT CLUTCH SOLENOID VALVE" , AT-129, "DTC P1705 THROTTLE
POSITION SENSOR" , AT-112, "DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION
SENSOR)" , AT-136, "DTC P1721 VEHICLE SPEED SENSOR MTR" .
NO >> GO TO 3.
3. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT-13, "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
4. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT- 5 9 , "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 7.
NG - 1 >> Line pressure high. GO TO 5.
NG - 2 >> Line pressure low. GO TO 6.
SAT6 3 8A
SAT4 9 4G

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-209
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Revision: August 20072004 QX56
4. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 7.
NG - 1 >> Line pressure high. GO TO 5.
NG - 2 >> Line pressure low. GO TO 6.
5. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
7. CHECK A/T FLUID CONDITION
1. Remove oil pan. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sensor 2" .
2. Check A/T fluid condition. Refer to AT- 5 8 , "
Fluid Condition
Check" .
OK or NG
OK >> GO TO 8.
NG >> GO TO 11.
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SCIA5199E

TROUBLE DIAGNOSIS FOR SYMPTOMS
AT-211
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Revision: August 20072004 QX56
P1705 THROTTLE POSITION SENSOR" , AT- 11 2 , "DTC P0720 VEHICLE SPEED SENSOR A/T
(REVOLUTION SENSOR)" , AT - 1 3 6 , "DTC P1721 VEHICLE SPEED SENSOR MTR" .
NO >> GO TO 3.
3. CHECK A/T FLUID LEVEL
Check A/T fluid level. Refer to AT- 1 3 , "
Checking A/T Fluid" .
OK or NG
OK >> GO TO 4.
NG >> Refill ATF.
4. CHECK LINE PRESSURE
Check line pressure at the engine stall point. Refer to AT-59, "
LINE
PRESSURE TEST" .
OK or NG
OK >> GO TO 7.
NG - 1 >> Line pressure high. GO TO 5.
NG - 2 >> Line pressure low. GO TO 6.
5. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
1. Check control valve with TCM. Refer to AT-241, "
Control Valve With TCM and A/T Fluid Temperature Sen-
sor 2" .
2. Disassemble A/T. Refer to AT- 2 7 3 , "
Disassembly" .
3. Check the following items:
–Oil pump assembly. Refer to AT-290, "Oil Pump" .
–Power train system. Refer to AT- 2 7 3 , "Disassembly" .
–Transmission case. Refer to AT - 2 7 3 , "Disassembly" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
SAT6 3 8A
SAT4 9 4G