INFINITI QX4 2001 Factory Service Manual

Diagnostic ProcedureNBTF0027
1 CHECK INPUT SIGNAL
WITHOUT CONSULT-II©GO TO 2.
2 CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ªOFFº position.
2. Disconnect ABS control unit harness connector.
3. Disconnect ABS control unit and transfer control unit harness connectors.
4. Check continuity between transfer control unit harness connector terminal 32 and ABS control unit harness connector
terminal 13.
Continuity should exist.
5. Check continuity between transfer control unit harness connector terminal 32, ABS control unit harness connector ter-
minal 13 and body ground.
No continuity should exist.
SMT793DA
OK or NG
OK©GO TO 3.
NG©Repair or replace harness or connector between ABS control unit and transfer control
unit.
3 CHECK COMMUNICATION LINE
Check communication line between ABS control unit and transfer control unit.
(Refer to BR-77, ª8. Vehicle vibrates excessively when ABS is operatingº.)
OK or NG
OK©GO TO 4.
NG©Check, repair or replace faulty parts.
ABS OPERATION SIGNAL
Diagnostic Procedure
TF-86

4 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
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LC
EC
FE
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PD
AX
SU
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IDX
ABS OPERATION SIGNAL
Diagnostic Procedure (Cont'd)
TF-87

Diagnostic ProcedureNBTF0028
1 CHECK TRANSFER CONTROL UNIT POWER SOURCE
1. Turn ignition switch to ªOFFº position and perform self-diagnosis again.
Refer to ªTrouble Diagnosis without CONSULT-IIº, TF-27 and ªTrouble Diagnosis with CONSULT-IIº, TF-30.
2. Turn ignition switch to ªOFFº position.
3. Disconnect transfer control unit harness connector.
4. Check voltage between transfer control unit harness connector terminal 47 and body ground.
Voltage: Battery voltage
SMT794D
OK or NG
OK©GO TO 2.
NG©Check the following.
INo. 24 fuse (7.5A)
IHarness continuity between fuse and transfer control unit
2 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.
DATA ERASE/DISPLAY
Diagnostic Procedure
TF-88

Diagnostic ProcedureNBTF0064
1 SHIFT ACTUATOR
Refer to ªActuator & Actuator Position Switchº, ªCOMPONENT INSPECTIONº, TF-115.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 CHECK POWER SOURCE
SMT825DA
1. Disconnect transfer control device terminal.
2. Turn ignition switch to ªONº. (Do not start engine.)
3. Check voltage between transfer control device harness connector 3 (or 4) and body ground while 4WD shift switch is
set from 4H to 4LO (or from 4LO to 4H).
Voltage: Battery voltage
OK or NG
OK©Repair or replace actuator.
NG©1. Recheck the following.
IContinuity between ignition switch and transfer HI & LOW relays
IIgnition switch and No. 3 fuse (20A)
IContinuity between transfer shift HI & LOW relays and transfer control device
2. If NG, repair or replace damaged part.
3 CHECK INPUT SIGNAL
WITH CONSULT-II©GO TO 4.
WITHOUT CONSULT-II©GO TO 5.
GI
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SHIFT ACTUATOR
Diagnostic Procedure
TF-89

4 CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine (idling).
2. Select ªSELF-DIAG RESULTSº in Select Diag Mode.
3. Read out self-diagnostic result.
SMT826D
SMT978D
OK or NG
OK©GO TO 7.
NG©GO TO 6.
SHIFT ACTUATOR
Diagnostic Procedure (Cont'd)
TF-90

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Start engine (idling).
2. Check voltage between transfer control unit harness connector terminal 33 (or 42) and body ground while 4WD shift
switch is set from 4H to 4LO (or from 4LO to 4H).
SMT828D
3. Result
MTBL0202
OK or NG
OK©GO TO 7.
NG©GO TO 6.
6 CHECK HARNESS CONTINUITY BETWEEN TRANSFER CONTROL UNIT AND TRANSFER CONTROL
DEVICE
OK or NG
OK©GO TO 7.
NG©Repair and replace harness connector between transfer control unit and transfer control
device.
7 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/output signal inspection. Refer to ªTRANSFER CON-
TROL 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
SHIFT ACTUATOR
Diagnostic Procedure (Cont'd)
TF-91

Diagnostic ProcedureNBTF0065
1 SHIFT ACTUATOR POSITION SWITCH
Refer to ªActuator & Actuator Position Switchº, ªCOMPONENT INSPECTIONº, TF-115.
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 CHECK POSITION SWITCH
1. Recheck continuity of shift actuator position switch.
Refer to ªActuator & Actuator Position Switchº, ªCOMPONENT INSPECTIONº, TF-115.
Continuity should exist.
OK or NG
OK©GO TO 3.
NG©Repair or replace position switch.
3 CHECK INPUT SIGNAL
WITH CONSULT-II©GO TO 4.
WITHOUT CONSULT-II©GO TO 5.
4 CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine (idling).
2. Select ªSELF-DIAG RESULTSº in Select Diag Mode.
3. Read out self-diagnostic result.
SMT829DA
SMT978D
OK or NG
OK©GO TO 7.
NG©GO TO 6.
SHIFT ACTUATOR POSITION SWITCH
Diagnostic Procedure
TF-92

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Start engine (idling).
2. Check voltage transfer control unit harness connector terminal 27 (or 44) and body ground while 4WD shift switch is
set from 4H to 4LO (or from 4LO to 4H).
SMT830D
3. Result
MTBL0203
OK or NG
OK©GO TO 7.
NG©GO TO 6.
6 CHECK HARNESS CONTINUITY BETWEEN TRANSFER CONTROL UNIT AND TRANSFER CONTROL
DEVICE
OK or NG
OK©GO TO 7.
NG©Repair and replace harness connector between transfer control unit and transfer control
device.
7 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/output signal inspection. Refer to ªTRANSFER CON-
TROL 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
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IDX
SHIFT ACTUATOR POSITION SWITCH
Diagnostic Procedure (Cont'd)
TF-93

Diagnostic ProcedureNBTF0066
1 SHIFT ACTUATOR CIRCUIT
Refer to ªTransfer Shift Relay (High & Low)º, ªCOMPONENT INSPECTIONº and ªActuator & Actuator Position Switchº,
ªCOMPONENT INSPECTIONº, TF-114, 115.
OK or NG
OK©GO TO 2.
NG©Repair or replace transfer shift relay and actuator and actuator position switch.
2 CHECK POWER SOURCE OF TRANSFER SHIFT (HI & LOW) RELAY
SMT825DA
1. Disconnect transfer control device terminal.
2. Turn ignition switch to ªONº (Do not start engine).
3. Check voltage between transfer shift HI and LOW relay terminal 5 and body ground.
Voltage: Battery voltage
SMT831D
OK or NG
OK©GO TO 3.
NG©Check the following.
IContinuity between ignition switch and transfer shift HI & LOW relays
ICheck ground circuit between transfer shift HI & LOW relays and body ground.
IIgnition switch and No. 3 fuse (20A)
SHIFT ACTUATOR CIRCUIT
Diagnostic Procedure
TF-94

3 CHECK POWER SOURCE OF TRANSFER CONTROL DEVICE
1. Disconnect transfer control device terminal.
2. Turn ignition switch to ªONº. (Do not start engine.)
3. Turn 4WD shift switch from ª4Hº to ª4LOº (or from ª4LOº to ª4Hº).
4. Check voltage between transfer control device terminal 3 (or 4) and body ground.
Voltage: Battery voltage
SMT832D
OK or NG
OK©GO TO 4.
NG©Check the following.
IHarness and connector from transfer shift HI and LOW relays to transfer control
device harness terminal
IGround circuit between transfer control device and body ground.
4 CHECK INPUT SIGNAL
WITH CONSULT-II©GO TO 5.
WITHOUT CONSULT-II©GO TO 6.
GI
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LC
EC
FE
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PD
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SU
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ST
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BT
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IDX
SHIFT ACTUATOR CIRCUIT
Diagnostic Procedure (Cont'd)
TF-95