2001 INFINITI QX4 clutch

4 CHECK INPUT SIGNAL
SMT790D
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out the ON/OFF status of ªLINE PRES SWº.
SMT977D
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
ITransfer sub-harness
ILine pressure switch
Refer to ª4WD Solenoid Valve, Clutch Pressure Switch and Line Pressure Switchº,
ªCOMPONENT INSPECTIONº, TF-111.
LINE PRESSURE SWITCH
Diagnostic Procedure (Cont'd)
TF-84

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ªOFFº position.
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connector terminal 35 and body ground.
After the vehicle has been left for at least 5 minutes in a room temperature with ignition switch ªOFFº:
No continuity should exist.
With ignition switch in ªONº, 4WD shift switch in ªAUTOº or ª4Hº and A/T selector lever in ªDº:
Continuity should exist.
SMT791D
SMT849D
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
ITransfer sub-harness
ILine pressure switch
Refer to ª4WD Solenoid Valve, Clutch Pressure Switch and Line Pressure Switchº,
ªCOMPONENT INSPECTIONº, TF-111.
6 PERFORM SELF-DIAGNOSIS AGAIN
1. Check hydraulic parts.
2. 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 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
LINE PRESSURE SWITCH
Diagnostic Procedure (Cont'd)
TF-85

Symptom 8. Tight Corner Braking SymptomNBTF0036SYMPTOM: Tight corner braking symptom occurs. (Hydraulic
system failure)
1 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out the ON/OFF status of ªCLUTCH PRES SWº.
SMT977D
Without CONSULT-II
Check voltage between transfer control unit harness connector terminal 34 and body ground.
Refer to ªTRANSFER CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONº,
TF-55.
OK or NG
OK©Disassemble transfer unit and check the following.
IControl valve assembly
I4WD solenoid valve
I2-4WD shift solenoid valve
IClutch piston
IClutch assembly
NG©GO TO 2.
2 CHECK CLUTCH PRESSURE SWITCH CIRCUIT
Check clutch pressure switch circuit.
Refer to ªDiagnostic Procedureº, ªCLUTCH PRESSURE SWITCHº, TF-80.
OK or NG
OK©GO TO 3.
NG©Check, repair or replace faulty parts.
3 CHECK PROCEDURES FROM THE BEGINNING AGAIN
Check again.
OK or NG
OK©INSPECTION END
NG©Recheck each connector's pin terminals for damage or loose connection.
TROUBLE DIAGNOSES FOR SYMPTOMS
Symptom 8. Tight Corner Braking Symptom
TF-108

Symptom 9. 4WD System Does Not Operate=NBTF0037SYMPTOM: The vehicle cannot be put into 4WD mode.
(Hydraulic system failure)
1 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out the ON/OFF status of ªCLUTCH PRES SWº.
SMT977D
Without CONSULT-II
Check voltage between transfer control unit harness connector terminal 34 and body ground.
Refer to ªTRANSFER CONTROL UNIT INSPECTION TABLEº, ªTROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONº,
TF-55.
OK or NG
OK©1. Check transfer fluid level.
2. Disassemble transfer unit and check the following.
ITransfer motor
IMain oil pump assembly
ISub-oil pump assembly
IOil strainer
IControl valve assembly
I2-4WD shift solenoid valve
IOil filter element
ILip seal
IStrainer O-ring
IMain oil pump drive gear
ISeal ring
ID-ring
IClutch piston
IClutch assembly
NG©GO TO 2.
2 CHECK CLUTCH PRESSURE CIRCUIT
Check clutch pressure switch circuit.
Refer to ªDiagnostic Procedureº, ªCLUTCH PRESSURE SWITCHº, TF-80.
OK or NG
OK©GO TO 3.
NG©Check, repair or replace faulty parts.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SYMPTOMS
Symptom 9. 4WD System Does Not Operate
TF-109

NBTF0038
SMT858D
4WD Shift SwitchNBTF0038S01Check continuity between each terminal.
Terminals Switch position Continuity
1-22WD Yes
Except 2WD No
1-3,1-4AUTO Yes
Except AUTO No
1-4,1-54H Yes
Except 4H No
1-4,1-64LO Yes
Except 4LO No
SMT079D
2-4WD Shift Solenoid Valve and Transfer Fluid
Temperature Sensor
NBTF0038S02Measure resistance between terminals of transfer terminal cord
assembly sub-harness connector located on rear-right of transfer
unit.
Component parts Terminals Resistance
2-4WD shift solenoid valve 4 - 5Approx. 20ÉC (68ÉF):
Approx. 22.8 - 25.2W
Transfer fluid temperature
sensor2-3Approx. 20ÉC (68ÉF): Approx. 2.5 kW
Approx. 80ÉC (176ÉF): Approx. 0.3
kW
SMT080D
4WD Solenoid Valve, Clutch Pressure Switch
and Line Pressure Switch
NBTF0038S03Measure resistance between terminals of transfer terminal cord
assembly sub-harness connector located on rear-right of transfer
unit.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
COMPONENT INSPECTION
4WD Shift Switch
TF-111

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

SMT087D
TRANSFER SWITCH ASSEMBLY SUB-HARNESS
CONNECTOR
NBTF0038S0902Check continuity between terminals shown in the figure.
SMT088D
TRANSFER TERMINAL CORD ASSEMBLY
SUB-HARNESS CONNECTOR
NBTF0038S0903Check continuity between terminals shown in the figure.
Terminals on solenoid valve
Terminals Components
6 4WD solenoid valve
4, 5 2-4WD shift solenoid valve
2, 3 Transfer fluid temperature sensor
7 Clutch pressure switch
1 Line pressure switch
SMT807D
Transfer Shift Relay (High & low)NBTF0038S10Check continuity between terminals 3 and 4.
Condition Continuity
12V direct current supply
between terminals 1 and 2No
No current supply Yes
COMPONENT INSPECTION
Transfer Sub-harness (Cont'd)
TF-114

Transfer ComponentsNBTF0076
SMT810D
1. Oil seal
2. Transfer cover
3. Snap ring
4. Washer
5. Snap ring
6. Main gear bearing
7. Front case
8. Check plug
9. Check spring
10. Check ball
11. Internal gear
12. Snap ring
13. Bearing race
14. Thrust needle bearing
15. Planetary carrier
16. Thrust needle bearing
17. Sun gear18. L-H sleeve
19. 2-4 sleeve
20. Radial needle bearing
21. Front revolution sensor
22. Roll pin
23. L-H fork
24. 2-4 fork
25. Shift fork spring
26. Fork guide
27. Roll pin
28. Shift rod
29. Self-lock nut
30. Companion flange
31. Oil seal
32. Drain plug
33. Wait detection switch
34. Needle bearing35. Mainshaft
36. Drive chain
37. Clutch drum
38. Clutch hub
39. Snap ring
40. Driven plate
41. Drive plate
42. Retaining plate
43. Return spring assembly
44. Press flange
45. Washer
46. Thrust needle bearing
47. Snap ring
48. Seal ring
49. Front bearing
50. Front drive shaft
51. Rear bearing
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
OVERHAUL
Transfer Components
TF-121