air condition INFINITI QX56 2006 Factory Service Manual

TROUBLE DIAGNOSISTF-35
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
NOTE:

Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not
a malfunction.

Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is "4H" or "4LO", steering wheel is turned fully to either side.
Transfer Control Unit Input/Output Signal Reference ValuesEDS002HJ
TRANSFER CONTROL UNIT INSPECTION TABLE
Specifications with CONSULT-II
4WD warning lamp flashes slowly
(1 time/2 seconds)While drivingTire size is different between front and
rear of vehicle.
TF-129
Transfer fluid temperature
Clutch pressure switch
Heavy tight-corner braking symptom occurs
(See NOTE.)

While driving

AUTO mode

Steering wheel is
turned fully to either
side CAN communication line
TF-130
4WD shift switch
Accelerator pedal position signal
Clutch pressure solenoid
Transfer inner parts
4WD system does not operate While driving 4WD shift switch
TF-131
Clutch pressure switch
Transfer inner parts
Symptom
ConditionCheck itemReference page
Monitored item [Unit] Content ConditionDisplay value
VHCL/S SEN ·FR [km/h]
or [mph] Front wheel speed Vehicle stopped
0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±
10%)
VHCL/S SEN ·RR [km/h]
or [mph] Rear wheel speed Vehicle stopped
0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±
10%)
ENGINE SPEED [rpm] Engine speed Engine stopped
(Engine speed: Less than 400 rpm)
0 rpm
Engine running
(Engine speed: 400 rpm or more) Approximately
equal to the indi-
cation on tachom-
eter
THRTL POS SEN [V] Accelerator pedal posi-
tion (APP) sensor signal
voltage Accelerator pedal: Release
Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V] Transfer fluid tempera-
ture signal voltage Transfer fluid temperature approx. 20 - 80°C (68 - 176
°F) Approx. 1.1 - 0.3V
BATTERY VOLT [V] Power supply voltage for
transfer control unit
Ignition switch: ON
Battery voltage
2WD SWITCH [ON/OFF] Input condition from
4WD shift switch 4WD shift switch: 2WD
ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF] Input condition from
4WD shift switch 4WD shift switch: AUTO
ON
4WD shift switch: 2WD, 4H or 4LO OFF

TROUBLE DIAGNOSISTF-37
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
P POSI SW AT [ON/
OFF]Input condition from A/T
PNP switch
Vehicle stopped

Engine running

Brake pedal depressed A/T selector lever posi-
tion: P
ON
Except the above OFF
ABS OPER SW [ON/
OFF] Condition of ABS operat-
ing ABS is operating.
ON
ABS is not operating. OFF
VDC OPER SW [ON/
OFF] Condition of VDC operat-
ing VDC is operating.
ON
VDC is not operating. OFF
TCS OPER SW [ON/
OFF] Condition of TCS operat-
ing TCS is operating.
ON
TCS is not operating. OFF
THROTTLE POSI [0.0/8] Condition of throttle
opening When depressing accelerator pedal
(Value rises gradually in response to throttle position.)
0.0/8 - 8.0/8
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” posi-
tion

Brake pedal depressed 4WD shift switch: 2WD
2WD
4WD shift switch: AUTO AUTO
4WD shift switch: 4H LOCK
4WD shift switch: 4LO 4L
VHCL/S COMP [km/h] or
[mph] Vehicle speed Vehicle stopped
0 km/h (0 MPH)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indi-
cation on speed-
ometer (Inside of
±
10%)
COMP CL TORQ [kgm] Condition of control
torque

Vehicle stopped

Engine running

A/T selector lever “
N” posi-
tion

Brake pedal depressed 4WD shift switch: 2WD 0 kg-m
4WD shift switch: AUTO
39 - 1,353 N
·m
(4 - 138 kg-m, 29 - 998 ft-lb)
4WD shift switch: 4H or
4LO 1,353 N
·m
(138 kg-m, 998 ft- lb)
DUTY SOLENOID [%] Condition of clutch pres-
sure solenoid

Vehicle stopped

Engine running

A/T selector lever “
N” posi-
tion

Brake pedal depressed 4WD shift switch: 2WD
4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO 4%
2-4WD SOL [ON/OFF] Condition of 2-4WD shift
solenoid valve

Vehicle stopped

Engine running

A/T selector lever “
N” posi-
tion

Brake pedal depressed 4WD shift switch: 2WD
OFF
4WD shift switch: AUTO ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
( “ Wait ” function is operat-
ing.) OFF
4WD shift switch: 4H
( “ Wait ” function is operat-
ing.) OFF
Monitored item [Unit]
Content ConditionDisplay value

TF-60
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
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.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 25 and neutral-4LO switch harness connector
F60 terminal 13.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value

Vehicle stopped

Engine running

A/T selector lever “N ” position

Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.) OFF →
ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→ OFF
4WD shift switch: 4LO ON
SDIA2692E
ConnectorTerminal
(Wire
color) Condition
Voltage
(Approx.)
E143 25 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N ” position

Brake pedal
depressed 4WD shift switch:
2WD, AUTO or 4H
Battery
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
Continuity should exist.
SDIA2694E

TROUBLE DIAGNOSIS FOR SYSTEMTF-61
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
3. CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect neutral-4LO switch harness connector.
3. Check continuity between neutral-4LO switch harness connec- tor F60 terminal 12 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.
4. CHECK 4LO SWITCH
1. Turn ignition switch “OFF”.
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.
OK or NG
OK >> GO TO 5.
NG >> Replace neutral-4LO switch. Refer to TF-22, "
Location
of Electrical Parts" .
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE 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-132, "
Removal and Installation" .
Continuity should exist.
SDIA2695E
Terminal
Condition Continuity
12 - 13 Push neutral-4LO switch
Yes
Release neutral-4LO switch No
SDIA2696E

TROUBLE DIAGNOSIS FOR SYSTEMTF-65
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
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.
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-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE 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-132, "
Removal and Installation" .
Connector TerminalConditionContinuity
M141 1 - 2
4WD shift switch: 2WD
Yes
4WD shift switch: AUTO, 4H and
4LO No
1 - 3 4WD shift switch: AUTO
Yes
4WD shift switch: 2WD, 4H and
4LO No
1 - 4 4WD shift switch: 2WD
No
4WD shift switch: AUTO, 4H and
4LO Ye s
1 - 5 4WD shift switch: 4H
Yes
4WD shift switch: 2WD, AUTO,
and 4LO No
1 - 6 4WD shift switch: 4LO
Yes
4WD shift switch: 2WD, AUTO
and 4H No
WDIA0205E

TROUBLE DIAGNOSIS FOR SYSTEMTF-67
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK WAIT DETECTION 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 “WAIT DETCT SW”.
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 WAIT DETECTION SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the wait detection switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 43 and wait detection switch harness connec-
tor F59 terminal 10.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value

Vehicle stopped

Engine running

A/T selector lever “N” position

Brake pedal depressed 4WD shift switch: 2WD, AUTO
or 4H
OFF
4WD shift switch: 4H to 4LO
(While actuator motor is operat-
ing.) OFF
→ ON
4WD shift switch: 4LO to 4H
(While actuator motor is operat-
ing.) ON →
OFF
4WD shift switch: 4LO ON
PDIA0221E
Connector Terminal ConditionVoltage
(Approx.)
E143 43 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N ” position

Brake pedal
depressed 4WD 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 actuator
motor is operating.) 0V
→
Battery
voltage
4WD shift switch: 4LO 0VSDIA2701E
Continuity should exist.
SDIA2702E

TF-68
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
3. CHECK GROUND CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect wait detection switch harness connector.
3. Check continuity between wait detection switch harness con- nector F59 terminal 11 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.
4. CHECK WAIT DETECTION SWITCH
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect wait detection switch harness connector.
3. Remove wait detection switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release wait detection switch and check continuity between wait detection switch terminals 10 and 11.
OK or NG
OK >> GO TO 5.
NG >> Replace wait detection switch. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE 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-132, "
Removal and Installation" .
Continuity should exist.
SDIA2703E
Terminal
Condition Continuity
10 - 11 Push wait detection switch
Yes
Release wait detection switch No
SDIA2704E

TROUBLE DIAGNOSIS FOR SYSTEMTF-69
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect wait detection switch harness connector.
3. Remove wait detection switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release wait detection switch and check continuity between wait detection switch terminals 10 and 11.
5. If NG, replace the wait detection switch. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
PNP Switch Signal (TCM)EDS002IB
DIAGNOSTIC PROCEDURE
1. CHECK DTC WITH TCM
Perform self-diagnosis with TCM. Refer to TF-50, "
SELF-DIAGNOSTIC PROCEDURE (WITH CONSULT-II)" .
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 Values" .
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-50, "
SELF-DIAGNOSTIC PROCEDURE
(WITH CONSULT-II)" .
TerminalCondition Continuity
10 - 11 Push wait detection switch
Yes
Release wait detection switch No
SDIA2704E

TF-72
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
2. CHECK ACTUATOR MOTOR POWER SUPPLY CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shift high relay and transfer shift low relay.
3. Check voltage between transfer shift high relay harness connec- tor E46 terminal 5 (A), transfer shift low relay harness connector
E47 terminal 5 (B) and ground.
4. Turn ignition switch “ ON”. (Do not start engine.)
5. Check voltage between transfer shift high relay harness connec- tor E46 terminal 5 (A), transfer shift low relay harness connector
E47 terminal 5 (B) 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. 57, located in the fuse block (J/B)]. Refer to PG-4, "POWER SUPPLY ROUTING
CIRCUIT" .

Harness for short or open between battery, transfer shift high relay harness connector terminal
5 and transfer shift low relay harness connector terminal 5.
E14333 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N ” position

Brake pedal
depressed 4WD shift switch: 4H
to 4LO (
“Wait ” function
is operating.) Battery
voltage
Except the above 0V
42 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N ” position

Brake pedal
depressed 4WD shift switch: 4LO
to 4H (
“Wait ” function
is operating.) Battery
voltage
Except the above 0V
Connector Terminal
ConditionVoltage
(Approx.)
Connector Terminal Voltage (Approx.)
E46 5 - Ground
Battery voltage
E47 5 - Ground
WDIA0310E
Connector Terminal Voltage (Approx.)
E46 5 - Ground
Battery voltage
E47 5 - Ground
WDIA0311E

TROUBLE DIAGNOSIS FOR SYSTEMTF-73
CE F
G H
I
J
K L
M A
B
TF
Revision: November 2009 2006 QX56
3. CHECK ACTUATOR MOTOR GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shift high relay and transfer shift low relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Check continuity between transfer shift high relay harness con- nector E46 terminals 2, 4 (A) and transfer shift low relay harness
connector E47 terminal 2, 4 (B) 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.
4. CHECK TRANSFER SHIFT RELAY
1. Turn ignition switch “OFF”.
2. Remove transfer shift high relay and transfer shift low relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer shift relay terminals 1 and 2.
4. Check continuity between relay terminals 3 and 4, 3 and 5.
OK or NG
OK >> GO TO 5.
NG >> Replace the transfer shut off relay. Refer to TF-22, "
Location of Electrical Parts" .
Continuity should exist.
WDIA0312E
Terminal
ConditionContinuity
3 - 4 12V direct current supply between terminals 1 and 2 No
OFF
Yes
3 - 5 12V direct current supply between terminals 1 and 2 Yes
OFF
No
WIIA0291E