2007 INFINITI QX56 air condition

TROUBLE DIAGNOSIS FOR SYSTEM
TF-91
< SERVICE INFORMATION >
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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

TROUBLE DIAGNOSIS FOR SYSTEM
TF-93
< SERVICE INFORMATION >
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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-96
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 35 and transfer terminal cord assembly har-
ness connector F56 terminal 1.
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-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Value".
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.
• Transfer control unit pin terminals for damage or loose connection with harness connector.
• Transfer control unit. Refer to TF-115, "
Removal and Installation".
4.CHECK LINE PRESSURE SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to TF-22, "
Location of Electrical Parts".
3. Push and release line pressure switch and check continuity
between transfer terminal cord assembly terminal 1 and ground.
OK or NG
OK >> GO TO 5.
NG >> Replace line pressure switch. Refer to TF-22, "
Location
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 toTF-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 line pressure switch. Refer to TF-22, "
Location of Electrical Parts". Continuity should exist.
SDIA2752E
Terminal Condition Continuity
1 -
GroundPush line pressure switch Yes
Release line pressure switch No
WDIA0172E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-97
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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

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

TROUBLE DIAGNOSIS FOR SYSTEM
TF-101
< SERVICE INFORMATION >
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4.CHECK ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts".
4. Push and release ATP switch and check continuity between ATP
switch terminals 8 and 9.
OK or NG
OK >> GO TO 5.
NG >> Replace ATP switch. Refer to TF-22, "
Location of Elec-
trical Parts".
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 ATP WARNING LAMP
1. Turn ignition switch “ON”. (Do not start engine.)
2. Move A/T selector lever to "P" position.
3. Set 4WD shift switch from "4H" to "4LO" or "4LO" to "4H".
Does ATP warning lamp turn ON while switching?
YES >> GO TO TF-109, "ATP Warning Lamp Turns ON" .
NO >> Inspection End.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 second.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts".
4. Push and release ATP switch and check continuity between ATP
switch terminals 8 and 9.
5. If NG, replace the ATP switch. Refer to TF-22, "
Location of Elec-
trical Parts".
Terminal Condition Continuity
8 - 9Push ATP switch Yes
Release ATP switch No
SDIA2757E
Terminal Condition Continuity
8 - 9Push ATP switch Yes
Release ATP switch No
SDIA2757E

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-111
< SERVICE INFORMATION >
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Dose 4WD shift indicator lamp keep flashing?
YES >> GO TO 2.
NO >> Inspection End.
2.CHECK SYSTEM FOR WAIT DETECTION SWITCH
Perform trouble diagnosis for wait detection switch system. Refer to TF-60, "
Wait Detection Switch".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.CHECK SYSTEM FOR NEUTRAL-4LO SWITCH
Perform trouble diagnosis for neutral-4LO switch system. Refer to TF-54, "
Neutral-4LO Switch".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 5.
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 TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to TF-128, "
Disassembly and Assembly".
2. Check transfer inner parts.
OK or NG
OK >> Inspection End.
NG >> Repair or replace damaged parts.
4WD Warning Lamp Flashes RapidlyINFOID:0000000003532558
SYMPTOM:
While driving, 4WD warning lamp flashes rapidly.
NOTE:
Rapid flashing: 2 times/second
DIAGNOSTIC PROCEDURE
1.CHECK TIRE
Check the following.
• Tire pressure
• Wear condition
• Longitudinal tire size (There is no difference between longitudinal tires.)
OK or NG
OK >> GO TO 2.
NG >> Repair or replace damaged parts.
2.CHECK 4WD WARNING LAMP
Stop the vehicle and allow it to idle for a short period of time.
Does flashing stop?

TF-112
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYMPTOMS
YES >> Inspection End.
NO >> GO TO 3.
3.CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fluid temperature system. Refer to TF-90, "
Transfer Fluid Temperature".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 5.
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 >> Inspection End.
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.
4WD Warning Lamp Flashes SlowlyINFOID:0000000003532559
SYMPTOM:
While driving, 4WD warning lamp flashes slowly. (When continuing to flash until turning ignition
switch OFF.)
NOTE:
Slow flashing: 1 time/2 seconds
DIAGNOSTIC PROCEDURE
1.CHECK TIRE
Check the following.
• Tire pressure
• Wear condition
• Longitudinal tire size (There is no difference between longitudinal tires.)
OK or NG
OK >> GO TO 2.
NG >> Repair or replace damaged parts.
2.CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fluid temperature system. Refer to TF-90, "
Transfer Fluid Temperature".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3.CHECK CLUTCH PRESSURE SWITCH
Perform trouble diagnosis for clutch pressure switch system. Refer to TF-92, "
Clutch Pressure Switch".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.