2007 INFINITI QX56 4WD

TF-86
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
MOTOR
RELAY
MON• Accelerator ped-
al depressed
• Vehicle stopped
• Engine running
• Brake pedal de-
pressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO or
4LO (A/T selector lever “P” or
“N” position)OFF
("ON" for ap-
prox. 2 sec. af-
ter shifting to
“P” and “N”.)
4WD shift switch: AUTO or
4LO (Except for A/T selector
lever “P” or “N” position)ON
4WD shift switch: 4H (A/T se-
lector lever “P” position)OFF
("ON" for ap-
prox. 2 sec. af-
ter shifting to
“P”.)
4WD shift switch: 4H (Except
for A/T selector lever “P” posi-
tion)ON Monitored
itemConditionDisplay value
(Approx.)
Connector Terminal Condition Voltage (Approx.)
E142 14 -
Ground• Accelera-
tor pedal
depressed
• Vehicle
stopped
•Engine
running
•Brake
pedal de-
pressed4WD shift switch:
2WDBattery voltage
4WD shift switch:
AUTO or 4LO (A/T
selector lever “P” or
“N” position)Battery voltage
(0V for approx. 2
sec. after shifting
to “P” and “N”.)
4WD shift switch:
AUTO or 4LO (Ex-
cept for A/T selector
lever “P” or “N” posi-
tion)0V
4WD shift switch: 4H
(A/T selector lever
“P” position)Battery voltage
(0V for approx. 2
sec. after shifting
to “P”.)
4WD shift switch: 4H
(Except for A/T se-
lector lever “P” posi-
tion)0V
SDIA2735E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-87
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
2.CHECK TRANSFER MOTOR RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Disconnect transfer motor relay.
4. Check voltage between transfer motor relay harness connector
terminals and ground.
5. Turn ignition switch “ON”. (Do not start engine.)
6. Check voltage between transfer motor relay harness connector
terminals and ground.
OK or NG
OK >> GO TO 3.
NG >> Check the following. If any items are damaged, repair
or replace damaged parts.
• 20A fuse No. 58 located in the fuse and relay box. Refer to PG-3
.
• 10A fuse No. 26 located in the fuse and fusible link box. Refer to PG-3
.
• Harness for short or open between battery and transfer motor relay harness connector E154 ter-
minal 5.
E143 41 -
Ground• Accelera-
tor pedal
depressed
• Vehicle
stopped
•Engine
running
•Brake
pedal de-
pressed4WD shift switch:
2WD0V
4WD shift switch:
AUTO or 4LO (A/T
selector lever “P” or
“N” position)0V
(Battery voltage
for approx. 2 sec.
after shifting to “P”
and “N”.)
4WD shift switch:
AUTO or 4LO (Ex-
cept for A/T selector
lever “P” or “N” posi-
tion)Battery voltage
4WD shift switch: 4H
(A/T selector lever
“P” position)0V
(Battery voltage
for approx. 2 sec.
after shifting to
“P”.)
4WD shift switch: 4H
(Except for A/T se-
lector lever “P” posi-
tion)Battery voltage Connector Terminal Condition Voltage (Approx.)
Connector Terminal Voltage (Approx.)
E153 2 - Ground 0V
E154 5 - Ground Battery voltage
WDIA0169E
Connector Terminal Voltage (Approx.)
E153 2 - Ground
Battery voltage
E154 5 - Ground
WDIA0170E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-89
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
3. Check continuity between transfer motor harness connector F57
terminal 15 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
6.CHECK TRANSFER MOTOR
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer motor harness connector.
3. Apply 12V direct current between transfer motor terminals 14
and 15.
Does transfer motor operate?
YES >> GO TO 7.
NO >> Replace transfer motor. Refer to TF-125, "
Removal and
Installation".
7.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-57, "
4WD Shift Switch".
OK or NG
OK >> GO TO 8.
NG >> Check transfer control unit pin terminals for damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
8.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> Inspection End.
NG >> Replace transfer control unit. Refer to TF-115, "
Removal and Installation".
COMPONENT INSPECTION
Transfer Motor Relay
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer motor relay. Refer to TF-22, "
Location of Electrical Parts".
3. Apply 12V direct current between transfer motor relay terminals
1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If NG, replace transfer motor relay. Refer to TF-22, "
Location of
Electrical Parts".
Transfer Motor
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)Continuity should exist.
SDIA2740E
LDIA0097E
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
LDIA0098E

TF-90
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
2. Remove transfer motor. Refer to TF-125, "Removal and Installation".
3. Apply 12V direct current between transfer motor terminals 14
and 15.
4. If transfer motor does not operate, replace transfer motor. Refer
to TF-125, "
Removal and Installation".
Transfer Fluid TemperatureINFOID:0000000003532544
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
DIAGNOSTIC PROCEDURE
1.CHECK TRANSFER FLUID TEMPERATURE SENSOR SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Read out the value of “FLUID TEMP SE”.
Without CONSULT-II
1. Start engine.
LDIA0097E
Monitored item [Unit] Content ConditionDisplay value
(Approx.)
FLUID TEMP SE [V]Condition of transfer fluid
temperatureTransfer fluid temperature approx. 20 - 80°C (68 -
176°F)1.1 - 0.3V
Te r m i n a lWire
colorItem Condition Data (Approx.)
28 B/G Sensor ground Always 0V
31 GTransfer fluid temperature
sensorIgnition switch: ONTransfer fluid temperature approx. 20°C
(68°F)1.1V
Transfer fluid temperature approx. 80°C
(176°F)0.3V
ConditionDisplay value
(Approx.)
Transfer fluid temperature approx. 20 - 80°C (68 - 176°F) 1.1 - 0.3V
SDIA2741E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-91
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
2. Check voltage between transfer control unit harness connector
terminals and ground.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER TERMINAL CORD AS-
SEMBLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer terminal cord assembly harness connec-
tor.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E143 terminal 28 and
transfer terminal cord assembly harness connector F56 terminal
3.
- Transfer control unit harness connector E143 terminal 31 and
transfer terminal cord assembly harness connector F56 terminal
2.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.CHECK TRANSFER FLUID TEMPERATURE SENSOR
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter-
minals 2 and 3.
OK or NG
OK >> GO TO 4.
NG >> Replace transfer fluid temperature sensor. Refer to TF-
22, "Location of Electrical Parts".
4.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-57, "
4WD Shift Switch".
OK or NG
OK >> GO TO 5.
NG >> Check transfer control unit pin terminals for damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
5.CHECK DTC
Connector Terminal ConditionData
(Approx.)
E14328 -
GroundAlways 0V
31 -
GroundIgnition switch:
ONTransfer fluid temperature
approx. 20°C (68°F)1.1V
Transfer fluid temperature
approx. 80°C (176°F)0.3V
SDIA2742E
Continuity should exist.
SDIA2743E
Temperature °C (°F) Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
WDIA0188E

TF-92
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> Inspection End.
NG >> Replace transfer control unit. Refer to TF-115, "
Removal and Installation".
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly har-
ness connector F56 terminals 2 and 3.
4. If NG, replace the transfer fluid temperature sensor. Refer to TF-
22, "Location of Electrical Parts".
Clutch Pressure SwitchINFOID:0000000003532545
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
DIAGNOSTIC PROCEDURE
1.CHECK CLUTCH PRESSURE SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
Temperature °C (°F) Resistance (Approx.)
20 (68) 2.5 kΩ
80 (176) 0.3 kΩ
WDIA0188E
Monitored item [Unit] Content Condition Display value
CL PRES SW [ON /
OFF]Condition of clutch pres-
sure switch• Vehicle stopped
• Engine running
• A/T selector lever “D” position
• 4WD shift switch: AUTO or 4H (“Wait” function is not
operating.)ON
• Vehicle stopped
• Engine running
• 4WD shift switch: 2WD (“Wait” function is not operat-
ing.)OFF
Te r m i n a lWire
colorItem Condition Data (Approx.)
34 BR Clutch pressure switch• Vehicle stopped
• Engine running
• A/T selector le-
ver “D” position4WD shift switch: AUTO or 4H (“Wait” func-
tion is not operating.)0V
• Vehicle stopped
• Engine running4WD shift switch: 2WD (“Wait” function is
not operating.)Battery voltage

TROUBLE DIAGNOSIS FOR SYSTEM
TF-93
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
3. Read out ON/OFF switching action of the “CL PRES SW” while
operating 4WD shift switch.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminals and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND CLUTCH PRESSURE SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 34 and transfer terminal cord assembly har-
ness connector F56 terminal 7
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-57, "
4WD Shift Switch".
OK or NG
OK >> GO TO 4.
NG >> Check transfer control unit pin terminals for damage or loose connection with the harness connec-
tor. If any items are damaged, repair or replace damaged parts.
4.CHECK CLUTCH PRESSURE SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to TF-22, "
Location of Electrical Parts".
Condition Display value
• Ignition switch: ON
• A/T selector lever “D” po-
sition4WD shift switch: AUTO or 4H
(“Wait” function is not operating.)ON
Ignition switch: ON4WD shift switch: 2WD (“Wait” func-
tion is not operating.)OFF
Connector Terminal ConditionVoltage
(Approx.)
E14334 -
Ground• Ignition switch: ON
• A/T selector lever
“D” position4WD shift switch:
AUTO or 4H
(“Wait” function is
not operating.)0V
Ignition switch: ON4WD shift switch:
2WD (“Wait” func-
tion is not operat-
ing.)Battery
voltage
WDIA0141E
SDIA2746E
Continuity should exist.
SDIA2747E

TF-94
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
3. Push and release clutch pressure switch and check continuity
between transfer terminal cord assembly terminal 7 and ground.
OK or NG
OK >> GO TO 5.
NG >> Replace clutch pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts".
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> GO TO 6.
NG >> Replace transfer control unit. Refer to TF-115, "
Removal and Installation" .
6.CRUISE TEST
Perform cruise test. Refer to TF-31, "
Inspections Before Trouble Diagnosis".
OK or NG
OK >> Inspection End.
NG >> Perform the applicable trouble diagnosis.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to TF-22, "
Location of Electrical Parts".
3. Push and release clutch pressure switch and check continuity
between transfer terminal cord assembly terminal 7 and ground.
4. If NG, replace the clutch pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts".
Line Pressure SwitchINFOID:0000000003532546
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Terminal Condition Continuity
7 -
GroundPush clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E
Terminal Condition Continuity
7 - GroundPush clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E
Monitored item [Unit] Content Condition Display value
LINE PRES SW [ON/
OFF]Condition of line pressure
switch• A/T selector lever “D” position
• 4WD shift switch: 2WD, AUTO or 4HON
• Except the above
• The vehicle has been
left at room temperature
for 5 minutes and more
with ignition switch in
“OFF” position.• Ignition switch: ON
• A/T selector lever: "P"
or "N" position
• 4WD shift switch: other
than AUTOOFF