2007 INFINITI QX56 4WD

TF-50
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
CAUTION:
• If “CAN communication” is displayed with other DTCs, first perform the trouble diagnosis for CAN communication line.
• If “ABS operation signal”, “VDC operation signal" or “TCS operation signal" is displayed, first perform the trouble diagnosis
for ABS system.
• If “Output shaft revolution signal” is displayed, first perform the trouble diagnosis for A/T system.
NOTE:
• If "actuator position switch" or “actuator circuit” is displayed, first erase self-diagnostic results. ("Actuator position switch" or “actuator
circuit” may be displayed after installing transfer control unit or transfer assembly.)
• If “clutch pressure switch” or “line pressure switch” is displayed only while driving in reverse, check the continuity of “R” position on A/
T PNP switch. When there is nothing wrong with the electrical system, check the hydraulic system.
ERASE SELF-DIAGNOSIS
• In order to make it easier to find the cause of hard-to-duplicate malfunctions, malfunction information is
stored into the control unit as necessary during use by the user. This memory is not erased no matter how
many times the ignition switch is turned ON and OFF.
• However, this information is erased by turning ignition switch “OFF” after performing self-diagnostics or by
erasing the memory using the CONSULT-II.
17ABS operation signal
(from ABS)• Malfunction is detected in ABS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.TF-97, "ABS Operation
Signal (ABS)"
18 Wait detection switch• Improper signal from wait detection switch is input due to
open or short circuit.TF-60, "Wait Detection
Switch"
19 Actuator motor• Motor does not operate properly due to open or short cir-
cuit in actuator motor.
• Malfunction is detected in the actuator motor. (When
4WD shift switch is operated and actuator motor is not
operated)
• Malfunction is detected in transfer shift high relay and
transfer shift low relay.TF-64, "
Actuator Motor",
TF-51, "
Power Supply
Circuit for Transfer Con-
trol Unit"
20Actuator position
switch• Improper signal from actuator position switch is input due
to open or short circuit.
• Malfunction is detected in the actuator position switch.TF-69, "Actuator Posi-
tion Switch"
21 Actuator circuit• Transfer control device actuator circuit is shorted or open.
(Malfunctions are detected when motor relay circuit is
open/shorted or relay transfer shift circuit is open/short-
ed.)
• Malfunction occurs in transfer control device drive circuit.TF-72, "
Transfer Control
Device"
• Malfunction is detected in transfer shut off relay.TF-51, "
Power Supply
Circuit for Transfer Con-
trol Unit"
22VDC operation signal
(from VDC)• Malfunction is detected in VDC operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.TF-98, "VDC Operation
Signal (ABS)"
23TCS operation signal
(from TCS)• Malfunction is detected in TCS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.TF-98, "TCS Operation
Signal (ABS)"
24PNP switch signal
(from TCM)• When A/T PNP switch signal is malfunctioning or commu-
nication error between the vehicles.TF-63, "PNP Switch
Signal (TCM)"
Repeats flickering
every 2 to 5 sec.— Circuits that the self-diagnosis covers have no malfunction. —
Repeats flickering
every 0.25 sec.Data erase display• Power supply failure of memory back-up.
• Battery performance is poor.TF-51, "
Power Supply
Circuit for Transfer Con-
trol Unit"
No flickeringPNP switch or 4WD
shift switch• PNP switch or 4WD shift switch circuit is shorted or open.TF-63, "
PNP Switch
Signal (TCM)", TF-57,
"4WD Shift Switch"
Flickering pattern or
flickering conditionItems Malfunction Check items

TROUBLE DIAGNOSIS FOR SYSTEM
TF-53
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shut off relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer shut off relay termi-
nals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If NG, replace the transfer shut off relay. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Control UnitINFOID:0000000003532530
DIAGNOSTIC PROCEDURE
1.INSPECTION START
Do you have CONSULT-II?
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2.PERFORM SELF-DIAGNOSIS (WITH CONSULT-II)
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform the self-diagnosis again.
Is the
“CONTROL UNIT 1 [P1802]”, “CONTROL UNIT 2 [P1803]”, “CONTROL UNIT 3 [P1804]” or “CONTROL
UNIT 4 [P1809]” displayed?
YES >> Replace transfer control unit. Refer to TF-115, "Removal and Installation" .
NO >> Inspection End.
3.PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-II)
Without CONSULT-II
1. Perform the self-diagnosis and then erase self-diagnostic results. Refer to TF-48, "Self-Diagnosis Proce-
dure" and TF-48, "Self-Diagnosis Procedure" .
2. Perform the self-diagnosis again.
Do the self-diagnostic results indicate AD converter?
YES >> Replace transfer control unit. Refer to TF-115, "Removal and Installation" .
NO >> Inspection End.
Output Shaft Revolution Signal (TCM)INFOID:0000000003532531
DIAGNOSTIC PROCEDURE
1.CHECK DTC WITH TCM
Perform self-diagnosis with TCM. Refer to TF-48, "
Self-Diagnosis Procedure" ..
Is any malfunction detected by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 2.
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
SCIA1245E

TF-54
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
2.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-51, "
Power Supply Circuit for Transfer Control Unit"
.
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 TCM again. Refer to TF-48, "
Self-Diagnosis Procedure".
Vehicle Speed Sensor (ABS)INFOID:0000000003532532
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
OK >> Inspection End.
NG >> Perform self-diagnosis with ABS actuator and electric unit (control unit) again. Refer to BRC-26,
"CONSULT-II Function (ABS)".
Neutral-4LO SwitchINFOID:0000000003532533
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Monitored item Content Condition Display value
N POSI SW TF [ON/
OFF]Condition of neutral-4LO
switch• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal depressed4WD shift switch: 2WD,
AUTO or 4HOFF
4WD shift switch: 4H to
4LO (While actuator mo-
tor is operating.)OFF → ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.)ON → OFF
4WD shift switch: 4LO ON

TROUBLE DIAGNOSIS FOR SYSTEM
TF-55
< 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 4LO POSITION SWITCH 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 “N POSI SW TF”.
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 NEUTRAL-4LO SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the neutral-4LO switch harness connector.
Te r m i n a lWire
colorItem Condition Data (Approx.)
25 V Neutral-4LO switch• Vehicle stopped
• Engine running
• A/T selector le-
ver “N” position
• Brake pedal de-
pressed4WD shift switch: 2WD, AUTO or 4H Battery voltage
4WD shift switch: 4H to 4LO (While actua-
tor motor is operating.)Battery voltage
→ 0V
4WD shift switch: 4LO to 4H (While actua-
tor motor is operating.)0V → Battery
voltage
4WD shift switch: 4LO 0V
Condition Display value
• Vehicle stopped
• Engine running
• A/T selector lever “N” position
• Brake pedal depressed4WD shift switch: 2WD,
AUTO or 4HOFF
4WD shift switch: 4H to
4LO (While actuator mo-
tor is operating.)OFF → ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.)ON → OFF
4WD shift switch: 4LO ON
SDIA2692E
ConnectorTe r m i n a l
(Wire col-
or)ConditionVoltage
(Approx.)
E143 25 -
Ground• Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de-
pressed4WD shift switch:
2WD, AUTO or 4HBattery
voltage
4WD shift switch: 4H to
4LO (While actuator
motor is operating.)Battery
voltage
→ 0V
4WD shift switch: 4LO
to 4H (While actuator
motor is operating.)0V →
Battery
voltage
4WD shift switch: 4LO 0V
SDIA2693E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-57
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
2. Disconnect neutral-4LO switch harness connector.
3. Remove neutral-4LO switch. Refer to TF-22, "
Location of Electrical Parts".
4. Push and release neutral-4LO switch and check continuity
between neutral-4LO switch terminals 12 and 13.
5. If NG, replace the neutral-4LO switch. Refer to TF-22, "
Location
of Electrical Parts".
4WD Shift SwitchINFOID:0000000003532534
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 4WD SHIFT SWITCH SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
Terminal Condition Continuity
12 - 13Push neutral-4LO switch Yes
Release neutral-4LO switch No
SDIA2696E
Monitored item [Unit] Content Condition Display value
2WD SWITCH [ON/OFF]Input condition from 4WD
shift switch4WD shift switch: 2WD ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF]Input condition from 4WD
shift switch4WD shift switch: AUTO ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF]Input condition from 4WD
shift switch4WD shift switch: 4H ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF]Input condition from 4WD
shift switch4WD shift switch: 4LO ON
4WD shift switch: 2WD, AUTO or 4H OFF
4WD MODE [AUTO/
LOCK/2WD/4L]Control status of 4WD
(Output condition of 4WD
shift indicator lamp and
4LO indicator lamp)• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal depressed4WD shift switch: 2WD 2WD
4WD shift switch: AUTO AUTO
4WD shift switch: 4H LOCK
4WD shift switch: 4LO 4L
Te r m i n a lWire
colorItem Condition Data (Approx.)
9G/W4WD shift switch
(2WD)Ignition switch: ON4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 O4WD shift switch
(4H)Ignition switch: ON4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or 4LO 0V
23 R4WD shift switch
(4LO)Ignition switch: ON4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 LG/R4WD shift switch
(AUTO)Ignition switch: ON4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V

TF-58
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Read out ON/OFF switching action of the “2WD SWITCH”,
“AUTO SWITCH”, “LOCK SWITCH”, “4L SWITCH” with operat-
ing 4WD shift switch.
Without CONSULT-II
1. Turn ignition switch “ON”. (Do not 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 4WD SHIFT SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
3. Check voltage between 4WD shift switch harness connector ter-
minal 1 and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
SDIA2697E
Connector Terminal ConditionVoltage (Ap-
prox.)
E1429 - ground4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 - ground4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or
4LO 0V
23 - ground4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 - ground4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
WDIA0148E
Connector Terminal Voltage (Approx.)
M141 1 - Ground 0V
SDIA2383E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-59
< SERVICE INFORMATION >
C
E
F
G
H
I
J
K
L
MA
B
TF
N
O
P
5. Check voltage between 4WD shift switch harness connector ter-
minal 1 and ground.
OK or NG
OK >> GO TO 3.
NG >> Go to TF-51, "
Power Supply Circuit for Transfer Control
Unit".
3.CHECK HARNESS BETWEEN 4WD SHIFT SWITCH AND TRANSFER CONTROL UNIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the 4WD shift switch harness connector.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E142 terminal 9 and
4WD shift switch harness connector M141 terminal 2.
- Transfer control unit harness connector E142 terminal 18 and
4WD shift switch harness connector M141 terminal 5.
- Transfer control unit harness connector E142 terminal 23 and
4WD shift switch harness connector M141 terminal 6.
- Transfer control unit harness connector E142 terminal 24 and
4WD shift switch harness connector M141 terminal 3.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.
• Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 3.
• Power supply circuit for transfer control unit. Refer to PG-3
.
4.CHECK 4WD SHIFT SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
3. Operate 4WD shift switch and check continuity between 4WD
shift switch terminals.
Connector Terminal Voltage (Approx.)
M141 1 - Ground Battery voltage
PDIA0210E
Continuity should exist.SDIA2699E
Connector Terminal Condition Continuity
M1411 - 24WD shift switch: 2WD Yes
4WD shift switch: AUTO, 4H and
4LONo
1 - 34WD shift switch: AUTO Yes
4WD shift switch: 2WD, 4H and
4LONo
1 - 44WD shift switch: 2WD No
4WD shift switch: AUTO, 4H and
4LOYe s
1 - 54WD shift switch: 4H Yes
4WD shift switch: 2WD, AUTO,
and 4LONo
1 - 64WD shift switch: 4LO Yes
4WD shift switch: 2WD, AUTO and
4HNo
WDIA0205E

TF-60
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
OK or NG
OK >> GO TO 5.
NG >> Replace 4WD shift switch.
5.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 6.
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.
6.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
1. Turn ignition switch “OFF”. (Stay for at least 5 second.)
2. Disconnect 4WD shift switch harness connector.
3. Operate 4WD shift switch and check continuity between 4WD
shift switch terminals.
4. If NG, replace the 4WD shift switch.
Wait Detection SwitchINFOID:0000000003532535
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Connector Terminal Condition Continuity
M1411 - 24WD shift switch: 2WD Yes
4WD shift switch: AUTO, 4H and
4LONo
1 - 34WD shift switch: AUTO Yes
4WD shift switch: 2WD, 4H and
4LONo
1 - 44WD shift switch: 2WD No
4WD shift switch: AUTO, 4H and
4LOYe s
1 - 54WD shift switch: 4H Yes
4WD shift switch: 2WD, AUTO,
and 4LONo
1 - 64WD shift switch: 4LO Yes
4WD shift switch: 2WD, AUTO and
4HNo
WDIA0205E