INFINITI QX4 2001 Factory Service Manual

Diagnostic ProcedureNBTF0021
1 CHECK 2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Refer to ª2-4WD Shift Solenoid Valve and Transfer Fluid Temperature Sensorº, ªCOMPONENT INSPECTIONº, TF-111.
SMT778D
OK or NG
OK©GO TO 2.
NG©Check the following. If OK, repair or replace 2-4WD shift solenoid valve and 4WD
shift switch.
IContinuity of transfer sub-harness
Refer to ªTRANSFER TERMINAL CORD ASSEMBLY SUB-HARNESS CONNECTORº,
ªCOMPONENT INSPECTIONº, TF-114.
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Diagnostic Procedure
TF-66

2 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out ON/OFF status of ª2WD SWº and ªLOCK SWITCHº.
SMT974D
OK or NG
OK©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
NG©GO TO 3.
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LC
EC
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IDX
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Diagnostic Procedure (Cont'd)
TF-67

3 CHECK 4WD SHIFT SWITCH POWER SOURCE
1. Disconnect 4WD shift switch harness connector.
2. Turn ignition switch to ªONº position.
3. Check voltage between 4WD shift switch harness connector terminal 1 and body ground.
Voltage: Battery voltage
SMT852D
OK or NG
OK©GO TO 4.
NG©Check the following.
INo. 18 fuse (10A)
IContinuity between ignition switch and 4WD shift switch
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Diagnostic Procedure (Cont'd)
TF-68

4 CHECK HARNESS CONTINUITY
1. Turn ignition switch to ªOFFº position.
2. Check continuity between the following terminals:
ITransfer control unit 9 and 4WD shift switch 2 (2WD)
ITransfer control unit 18 and 4WD shift switch 5 (4H)
ITransfer control unit 24 and 4WD shift switch 3 (AUTO)
ITransfer control unit 23 and 4WD shift switch 6 (4LO)
ITransfer control unit 1 and Transfer terminal cord assembly sub-harness connector 4
I4WD shift switch 4 and Transfer terminal cord assembly sub-harness connector 5
Continuity should exist.
SMT853D
OK or NG
OK©GO TO 5.
NG©Repair harness or connector.
5 PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27.
OK or NG
OK©INSPECTION END
NG©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Diagnostic Procedure (Cont'd)
TF-69

Diagnostic ProcedureNBTF0022
1 CHECK TRANSFER MOTOR AND TRANSFER MOTOR RELAY
SMT782D
Refer to ªTransfer Motorº and ªTransfer Motor Relayº, ªCOMPONENT INSPECTIONº, TF-113.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 CHECK CONTINUITY
Check the following.
IContinuity of transfer sub-harness
Refer to ªTRANSFER SWITCH ASSEMBLY SUB-HARNESS CONNECTORº, ªCOMPONENT INSPECTIONº, TF-114.
OK or NG
OK©Repair or replace transfer motor and transfer motor relay.
NG©Repair or replace transfer sub-harness.
3 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªMAIN SIGNALSº in Data Monitor.
2. Read out ON/OFF status of ªMOTOR RELAYº.
SMT975D
3. When the value is different from standard value although ON/OFF switching occurs, check the following items.
IPNP switch, throttle position sensor and closed throttle position switch circuits
Refer to AT-99, ªDTC P0705 Park/Neutral Position Switchº, AT-176, ªDTC P1705 Throttle Position Sensorº and AT-184,
ªClosed Throttle Position Switch (idle position)º.
OK or NG
OK©GO TO 4.
NG©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
TRANSFER MOTOR AND TRANSFER MOTOR RELAY
Diagnostic Procedure
TF-70

4 CHECK TRANSFER MOTOR RELAY POWER SOURCE
1. Disconnect transfer motor relay harness connector.
2. Turn ignition switch to ªONº position.
3. Check voltage between transfer motor relay harness connector terminals 1, 3 and body ground.
Voltage: Battery voltage
SMT854DA
OK or NG
OK©GO TO 5.
NG©Check the following.
INo. 55 fuse (20A)
INo. 18 fuse (10A)
IHarness continuity between fuse and transfer motor relay
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TRANSFER MOTOR AND TRANSFER MOTOR RELAY
Diagnostic Procedure (Cont'd)
TF-71

5 CHECK HARNESS CONTINUITY
1. Turn ignition switch to ªOFFº position.
2. Check continuity between the following terminals.
ITransfer control unit 41 and Transfer motor 14
ITransfer control unit 41 and Transfer motor relay 2
ITransfer control unit 14 and Transfer motor relay 4
ITransfer motor 15 and body ground
Continuity should exist.
SMT855DA
OK or NG
OK©GO TO 6.
NG©Repair or replace harness or connector.
6 PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27 and ªTrouble Diagnosis with CONSULT-IIº, TF-30.
OK or NG
OK©INSPECTION END
NG©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
TRANSFER MOTOR AND TRANSFER MOTOR RELAY
Diagnostic Procedure (Cont'd)
TF-72

Diagnostic ProcedureNBTF0023
1 CHECK TRANSFER FLUID TEMPERATURE SENSOR
Refer to ª2-4WD Shift Solenoid Valve and Transfer Fluid Temperature Sensorº, ªCOMPONENT INSPECTIONº, TF-111.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 CHECK CONTINUITY
Check the following.
IContinuity of transfer sub-harness
Refer to ªTRANSFER TERMINAL CORD ASSEMBLY SUB-HARNESS CONNECTORº, ªCOMPONENT INSPECTIONº,
TF-114.
OK or NG
OK©Repair or replace fluid temperature sensor.
NG©Repair or replace transfer sub-harness.
3 CHECK INPUT SIGNAL
WITH CONSULT-II©GO TO 4.
WITHOUT CONSULT-II©GO TO 5.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TRANSFER FLUID TEMPERATURE SENSOR
Diagnostic Procedure
TF-73

4 CHECK INPUT SIGNAL
SMT784D
With CONSULT-II
1. Start engine.
2. Select ªECU INPUT SIGNALSº in Data Monitor.
3. Read out the value of ªFLUID TEMP SEº.
Voltage:
20ÉC (68ÉF): Approx. 1.5V
80ÉC (176ÉF): Approx. 0.5V
SMT974D
OK or NG
OK©GO TO 6.
NG©Check the following.
IContinuity between transfer control unit and transfer terminal cord assembly sub-har-
ness connector
TRANSFER FLUID TEMPERATURE SENSOR
Diagnostic Procedure (Cont'd)
TF-74

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ªONº position.
2. Check voltage between transfer control unit harness connector terminals 28 and 31.
Voltage:
20ÉC (68ÉF): Approx. 1.5V
80ÉC (176ÉF): Approx. 0.5V
SMT785D
OK or NG
OK©GO TO 6.
NG©Check the following.
IContinuity between transfer control unit and transfer terminal cord assembly sub-har-
ness connector
6 PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27.
OK or NG
OK©INSPECTION END
NG©1. Perform transfer control unit input/output signal inspection. Refer to ªTRANSFER
CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL
DESCRIPTIONº, TF-55.
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with
harness connector.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TRANSFER FLUID TEMPERATURE SENSOR
Diagnostic Procedure (Cont'd)
TF-75