2001 INFINITI QX4 check engine

4 CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select ªECU INPUT SIGNALSº in Data Monitor.
3. Read out the value of ªVEHICLE SPEED SENSOR (FRONT)º while driving.
SMT773D
SMT974D
4. Check if the value changes according to accelerating and decelerating the vehicle.
OK or NG
OK©GO TO 6.
NG©GO TO 7.
VEHICLE SPEED SENSOR (FRONT REVOLUTION SENSOR)
Diagnostic Procedure (Cont'd)
TF-62

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminals 38 and 28.
(Measure it in AC range.)
Voltage:
0 km/h (0 MPH): 0V
30 km/h (19 MPH): More than 1V
(Voltage rises gradually in response to vehicle speed.)
SMT774D
OK or NG
OK©GO TO 6.
NG©GO TO 7.
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.
7 CHECK HARNESS CONTINUITY BETWEEN TRANSFER CONTROL UNIT AND FRONT REVOLUTION
SENSOR SUB-HARNESS CONNECTOR
OK or NG
OK©GO TO 6.
NG©Repair or replace sub-harness connector between transfer control unit and front revolu-
tion sensor.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
VEHICLE SPEED SENSOR (FRONT REVOLUTION SENSOR)
Diagnostic Procedure (Cont'd)
TF-63

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

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
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
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
EL
IDX
SHIFT ACTUATOR POSITION SWITCH
Diagnostic Procedure (Cont'd)
TF-93