2001 INFINITI QX4 ignition

2 CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch to ªOFFº position.
2. Disconnect transfer control unit harness connector.
3. Measure resistance between transfer control unit harness connector terminals 6, 45 and body ground.
Resistance: 0W
SMT803D
OK or NG
OK©GO TO 3.
NG©Check continuity between transfer control unit and body ground.
3 CHECK 4WD WARNING LAMP CIRCUIT
Check the following.
I4WD warning lamp
IContinuity between ignition switch and 4WD warning lamp
IContinuity between 4WD warning lamp and transfer control unit
OK or NG
OK©GO TO 4.
NG©IRepair or replace harness or connector.
IReplace 4WD warning lamp.
4 CHECK PROCEDURES FROM THE BEGINNING AGAIN
Check again.
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
TROUBLE DIAGNOSES FOR SYMPTOMS
Symptom 2. 4WD Warning Lamp Does Not Turn ON (Cont'd)
TF-101

Symptom 5. 4LO Indicator Lamp Does Not Turn
ON
=NBTF0033SYMPTOM: When 4WD shift switch is set from ª4Hº to
ª4LOº position, 4LO indicator lamp does not turn ON.
1 CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
SMT958D
SMT851D
SMT979D
1. Disconnect battery negative terminal (þ), then transfer control unit connector.
2. Connect battery negative terminal (þ) and turn ignition switch ªONº (with engine stopped).
3. Check voltage across transfer control unit body-side connector terminals 47, 16 and body ground.
Voltage: Battery voltage
OK or NG
OK©GO TO 2.
NG©Check the following.
IContinuity between battery and transfer control unit
IIgnition switch (Refer to EL-9, ªPower Supply Routingº.)
INo. 24 fuse (7.5A), No. 8 fuse (10A) and No. 18 fuse (10A)
TROUBLE DIAGNOSES FOR SYMPTOMS
Symptom 5. 4LO Indicator Lamp Does Not Turn ON
TF-104

2 CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch ªOFFº, and disconnect transfer control unit connector.
2. Check for continuity between transfer control unit body-side connector terminals 6, 45 and body ground.
Continuity should exist.
OK or NG
OK©GO TO 3.
NG©Check the following.
IContinuity between transfer control unit and body ground
3 CHECK 4LO INDICATOR LAMP CIRCUIT
Disconnect battery negative terminal (þ) and check the following items:
1. Check condition of 4LO indicator lamp.
2. Check continuity between battery and 4LO indicator lamp.
3. Check continuity between 4LO indicator lamp and transfer control unit connector terminal 12.
4. Check condition of ATP switch.
5. Check condition of neutral-4LO switch.
6. Check continuity between neutral-4LO switch ground terminal 6 and body ground.
OK or NG
OK©GO TO 4.
NG©Check the following.
I4LO indicator lamp
INeutral-4LO switch
Refer to ªATP Switch, Neutral-4LO Switch and Wait Detection Switchº, ªCOMPONENT
INSPECTIONº, TF-112.
4 CHECK PROCEDURES FROM THE BEGINNING
Check again.
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
TROUBLE DIAGNOSES FOR SYMPTOMS
Symptom 5. 4LO Indicator Lamp Does Not Turn ON (Cont'd)
TF-105

Component
partsTerminals Remarks
4WD solenoid
valve6
Ground
terminalApprox. 20ÉC (68ÉF): Approx. 3.0 - 3.4W
Clutch pres-
sure switch7In room temperature
I2-4WD shift solenoid valve ªOFFº: No
continuity
I2-4WD shift solenoid valve and transfer
motor ªONº: Continuity exists
Line pressure
switch1In room temperature
ITurn ignition switch to ªOFFº position
and leave vehicle for more than 5 min-
utes. (OFF): No continuity
ITransfer motor ªONº: Continuity exists
SMT081D
Front Revolution SensorNBTF0038S04Measure resistance between terminals of front revolution sensor
sub-harness connector located on rear-right of transfer unit.
Terminals Resistance
16 - 17 500 - 650W
18 - 17 No continuity
18 - 16 No continuity
SMT806D
Transfer Dropping ResistorNBTF0038S07Check resistance between terminals.
Resistance: 11.2 - 12.8W
SMT083D
ATP Switch, Neutral-4LO Switch and Wait
Detection Switch
NBTF0038S06Measure resistance between terminals of transfer switch assembly
sub-harness connector located on rear-right of transfer unit.
COMPONENT INSPECTION
4WD Solenoid Valve, Clutch Pressure Switch and Line Pressure Switch (Cont'd)
TF-112