2007 INFINITI QX56 engine

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

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

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

TROUBLE DIAGNOSIS FOR SYSTEM
TF-95
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
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 LINE PRESSURE SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Read out ON/OFF switching action of “LINE 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 LINE 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.
Te r m i n a lWire
colorItem Condition Data (Approx.)
35 BR/W Line pressure switch• Ignition switch: ON
• A/T selector lever “D” posi-
tion• 4WD shift switch: AUTO 0V
• Except the above
• The vehicle has been left at
room temperature for 5 min-
utes and more with ignition
switch in “OFF” position.• Ignition switch: ON
• A/T selector lever: "P" or "N"
position
• 4WD shift switch: other than
AUTOBattery voltage
Condition Display value
• A/T selector lever “D” position
• 4WD shift switch: AUTOON
• Except the above
• The vehicle has been left
at room temperature for 5
minutes and more with ig-
nition switch in “OFF” po-
sition.• Ignition switch: ON
• A/T selector lever: "P" or "N" po-
sition
• 4WD shift switch: other than
AUTOOFF
Connector Terminal ConditionVoltage
(Approx.)
E14335 -
Ground• A/T selector lever
“D” position4WD shift switch:
AUTO0V
• 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 le-
ver: "P" or "N"
position
• 4WD shift
switch: other
than AUTOBattery
voltage
WDIA0142E
SDIA2751E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-97
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
3. Push and release line pressure switch and check continuity
between transfer terminal cord assembly terminal 1 and ground.
4. If NG, replace the line pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts".
Throttle Position Signal (ECM)INFOID:0000000003532547
DIAGNOSTIC PROCEDURE
1.CHECK DTC WITH ECM
Perform self-diagnosis with ECM. Refer to E C - 111 , "
CONSULT-II Function (ENGINE)".
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
2.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Value".
OK or NG
OK >> GO TO 3.
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.
3.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> Inspection End.
NG >> Perform self-diagnosis with ECM again. Refer to EC-111, "
CONSULT-II Function (ENGINE)".
ABS Operation Signal (ABS)INFOID:0000000003532548
DIAGNOSTIC PROCEDURE
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to BRC-26, "
CONSULT-II Func-
tion (ABS)" .
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
2.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Value".
OK or NG
OK >> GO TO 3.
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.
3.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
Terminal Condition Continuity
1 - GroundPush line pressure switch Yes
Release line pressure switch No
WDIA0172E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-99
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
CAN Communication LineINFOID:0000000003532551
DIAGNOSTIC PROCEDURE
1.CHECK CAN COMMUNICATION CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON” and start engine.
2. Select “SELF-DIAG RESULTS” mode for “ALL MODE AWD/4WD” within CONSULT-II.
3. Perform the self-diagnosis.
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Print CONSULT-II screen and go to LAN-40.
NO >> Inspection End.
ATP SwitchINFOID:0000000003532552
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 ATP SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
SDIA1850E
Monitored item [Unit] Content Condition Display value
ATP SWITCH [ON/OFF] Condition of ATP switch• Vehicle stopped
• Engine running
• A/T selector lever “N"
• Brake pedal depressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is
operating.) ON
Except the above OFF
Te r m i n a lWire
colorItem Condition Data (Approx.)
40 L ATP switch• Vehicle stopped
• Engine running
• A/T selector le-
ver “N"
• Brake pedal de-
pressed4WD shift switch: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)0V
Except the above Battery voltage

TF-100
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
3. Read out the value of “ATP SWITCH”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the ATP switch harness connector.
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 40 and ATP switch harness connector F55 ter-
minal 8.
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 GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Check continuity between ATP switch harness connector F55
terminal 9 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
Condition Display value
• Vehicle stopped
• Engine running
• A/T selector lever
“N"
• Brake pedal de-
pressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.) ON
Except the above OFF
SDIA2391E
Connector Terminal ConditionVoltage
(Approx.)
E14340 -
Ground• Vehicle stopped
• Engine running
• A/T selector lever
“N"
• Brake pedal de-
pressed4WD shift switch: 4H
to 4LO or 4LO to 4H
(While actuator motor
is operating.)0V
Except the aboveBattery
voltage
SDIA2755E
Continuity should exist.
SDIA2756E
Continuity should exist.
SDIA2394E