2006 INFINITI QX56 4WD

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-117
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Revision: November 2009 2006 QX56
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ONEDS002HM
SYMPTOM:
4WD shift indicator lamp and 4LO indicator lamp do not turn ON for approx. 1 second when turning
ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Check voltage between transfer control unit harness connector terminals and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 2.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.

Harness for short or open between battery and transfer control unit harness connector terminal
29.

Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1, and 3.

Harness for short or open between transfer shut off relay harness connector E69 terminal 2
and transfer control unit harness connector terminal 30.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5
and transfer control unit harness connector terminals 16 and 22.

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .

Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
ConnectorTerminal Voltage (Approx.)
E142 16 - Ground
0V
22 - Ground
E143 29 - Ground
30 - Ground
Battery voltage
47 - Ground
WDIA0165E
Connector Terminal Voltage (Approx.)
E142 16 - Ground
Battery voltage
22 - Ground
E143 29 - Ground
30 - Ground
0V
47 - Ground Battery voltage
WDIA0166E

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-121
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Revision: November 2009 2006 QX56
4WD Warning Lamp Does Not Turn ONEDS002HN
SYMPTOM:
4WD warning lamp does not turn ON when turning ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Check voltage between transfer control unit harness connector terminals and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.

Harness for short or open between battery and transfer control unit harness connector terminal
29.

Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1, and 3.

Harness for short or open between transfer shut off relay harness connector E69 terminal 2
and transfer control unit harness connector terminal 30.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5
and transfer control unit harness connector terminals 16 and 22.

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .

Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
ConnectorTerminal Voltage (Approx.)
E142 16 - Ground
0V
22 - Ground
E143 29 - Ground
30 - Ground
Battery voltage
47 - Ground
WDIA0165E
Connector Terminal Voltage (Approx.)
E142 16 - Ground
Battery voltage
22 - Ground
E143 29 - Ground
30 - Ground
0V
47 - Ground Battery voltage
WDIA0166E

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-123
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Revision: November 2009 2006 QX56
4. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and combination meter harness connector.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E142 terminal 5 and
combination meter harness connector M24 terminal 34.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK INDICATOR LAMP CIRCUIT
1. Connect combination meter harness connector.
2. Disconnect transfer control unit harness connector.
3. Turn ignition switch “ON”. (Do not start engine.)
4. Ground the following terminal using suitable wiring.
–Transfer control unit harness connector E142 terminal 5 and
ground.
Does 4WD warning lamp turn on?
OK >> GO TO 6.
NG >> Replace combination meter. Refer to IP-13, "
COMBINA-
TION METER" .
6. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 7.
7. 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 >> 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 Shift Indicator Lamp or 4LO Indicator Lamp Does Not ChangeEDS002HO
SYMPTOM:
4WD shift indicator lamp or 4LO indicator lamp does not change when switching 4WD shift switch.Continuity should exist.
WDIA0154E
SDIA2774E

TF-124
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE
1. CONFIRM THE SYMPTOM
Confirm 4WD shift indicator lamp and 4LO indicator lamp turn on when ignition switch is turned to ON.
Do 4WD shift indicator lamp and 4LO indicator lamp turn on?
YES >> GO TO 2.
NO >> Go to TF-117, "
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ON" .
2. CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to TF-62, "
4WD Shift Switch" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK SYSTEM FOR WAIT DETECTION SWITCH
Perform trouble diagnosis for wait detection switch system. Refer to TF-66, "
Wait Detection Switch" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4. CHECK SYSTEM FOR NEUTRAL-4LO SWITCH
Perform trouble diagnosis for neutral-4LO switch system. Refer to TF-59, "
Neutral-4LO Switch" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK SYSTEM FOR ATP SWITCH
Perform trouble diagnosis for ATP switch system. Refer to TF-113, "
ATP Switch" .
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6. CHECK SYSTEM FOR 2-4WD SOLENOID
Perform trouble diagnosis for 2-4WD solenoid system. Refer to TF-91, "
2-4WD Solenoid" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
7. CHECK SYSTEM FOR TRANSFER CONTROL DEVICE
Perform trouble diagnosis for transfer control device system. Refer to TF-81, "
Transfer Control Device" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
8. CHECK SYSTEM FOR ACTUATOR MOTOR
Perform trouble diagnosis for actuator motor system. Refer to TF-70, "
Actuator Motor" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-125
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Revision: November 2009 2006 QX56
9. CHECK SYSTEM FOR ACTUATOR POSITION SWITCH
Perform trouble diagnosis for actuator position switch system. Refer to TF-77, "
Actuator Position Switch" .
OK or NG
OK >> GO TO 10.
NG >> Repair or replace damaged parts.
10. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 11.
11 . 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 12.
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.
12. CHECK TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to TF-146, "
Disassembly and Assembly" .
2. Check transfer inner parts.
OK or NG
OK >> Inspection End.
NG >> Repair or replace damaged parts.
ATP Warning Lamp Turns ONEDS002HP
SYMPTOM:
ATP warning lamp turns ON when 4WD shift switch from “4H” to “4LO” or “4LO” to “4H” with A/T
selector lever “N” to “P” position.
DIAGNOSTIC PROCEDURE
1. CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to TF-50, "
Self-diagnostic Procedure" .
Do the self-diagnostic results indicate CAN communication?
YES >> Perform trouble diagnosis for CAN communication line. Refer to TF-113, "CAN Communication
Line" .
NO >> GO TO 2.
2. CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to TF-62, "
4WD Shift Switch" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK SYSTEM FOR PNP SWITCH SIGNAL
Perform trouble diagnosis for PNP switch signal system. Refer to TF-69, "
PNP Switch Signal (TCM)" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-127
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Revision: November 2009 2006 QX56
7. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 8.
8. 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 9.
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.
9. CHECK TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to TF-146, "
Disassembly and Assembly" .
2. Check transfer inner parts.
OK or NG
OK >> Inspection End.
NG >> Repair or replace damaged parts.
4LO Indicator Lamp Repeats FlashingEDS002HQ
SYMPTOM:
4LO lamp keeps flashing.
DIAGNOSTIC PROCEDURE
1. CONFIRM THE SYMPTOM
1. Set 4WD shift switch to “2WD”.
2. Move vehicle forward and backward, or drive straight increasing or decreasing under 20 km/h (12 MPH).
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-66, "
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-59, "
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.

TF-128
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
5. 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 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-146, "
Disassembly and Assembly" .
2. Check transfer inner parts.
OK or NG
OK >> Inspection End.
NG >> Repair or replace damaged parts.
4WD Warning Lamp Flashes RapidlyEDS002HR
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?
YES >> Inspection End.
NO >> GO TO 3.
3. CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fluid temperature system. Refer to TF-102, "
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.

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-129
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Revision: November 2009 2006 QX56
5. 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 >> 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 SlowlyEDS002HS
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-102, "
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-105, "
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.
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 Values" .
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.