2001 INFINITI QX4 Transfer Control Unit

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

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

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

4 CHECK INPUT SIGNAL
With CONSULT-II
1. Select ªECU INPUT SIGNALSº in Data Monitor.
2. Read out the ON/OFF status of ªATP SWº, ªNEUTRAL SWº and ªWAIT DETCT SWº.
SMT976D
OK or NG
OK©GO TO 6.
NG©Check the following.
IHarness continuity between transfer switch assembly sub-harness connector and
transfer control unit
IContinuity between transfer switch assembly sub-harness connector and body ground
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ATP SWITCH, WAIT DETECTION SWITCH AND NEUTRAL-4LO SWITCH
Diagnostic Procedure (Cont'd)
TF-77

5 CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ªOFFº position.
2. Operate 4WD shift switch and check continuity between the following terminals.
Continuity:
Terminal 40 (ATP switch) and body ground
ª4Hº position: No continuity should exist.
Between ª4Hº and ª4LOº: Continuity should exist.
ª4LOº position: No continuity should exist.
Terminal 25 (Neutral-4LO switch) and body ground
ª4Hº position: No continuity should exist.
ª4LOº position: Continuity should exist.
Terminal 43 (Wait detection switch) and body ground
ª4Hº position: No continuity should exist. (*1)
ª4LOº position: Continuity should exist.
*1: After setting from ª4LOº to ª4Hº, continuity exists while ªWaitº function is operating in ª4Hº position.
(No continuity exists when ªWaitº function is canceled.)
SMT787D
SMT849D
OK or NG
OK©GO TO 6.
NG©Check the following.
IHarness continuity between transfer switch assembly sub-harness connector and
transfer control unit
IContinuity between transfer switch assembly sub-harness connector and body ground
ATP SWITCH, WAIT DETECTION SWITCH AND NEUTRAL-4LO SWITCH
Diagnostic Procedure (Cont'd)
TF-78

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
ATP SWITCH, WAIT DETECTION SWITCH AND NEUTRAL-4LO SWITCH
Diagnostic Procedure (Cont'd)
TF-79

5 CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch to ªONº position.
2. Select ªECU INPUT SIGNALSº in Data Monitor.
3. Read out ON/OFF status of ªCL PRES SWº.
SMT788D
SMT977D
OK or NG
OK©GO TO 7.
NG©Check the following.
IContinuity between transfer control unit and transfer terminal cord assembly sub-har-
ness connector
ITransfer sub-harness
IClutch pressure switch
Refer to ª4WD Solenoid Valve, Clutch Pressure Switch and Line Pressure Switchº,
ªCOMPONENT INSPECTIONº, TF-111.
GI
MA
EM
LC
EC
FE
AT
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
CLUTCH PRESSURE SWITCH
Diagnostic Procedure (Cont'd)
TF-81