2006 INFINITI QX56 engine

TROUBLE DIAGNOSIS FOR SYSTEMTF-115
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Revision: November 2009 2006 QX56
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.
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 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 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-125, "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" .
Continuity should exist.
SDIA2394E
Terminal
Condition Continuity
8 - 9 Push ATP switch
Yes
Release ATP switch No
SDIA2757E

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

TF-118
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connec- tor E142 terminals 3, 6, E143 terminal 45 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK COMBINATION METER POWER SUPPLY CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check voltage between combination meter harness connector terminal and ground.
4. Turn ignition switch “ ON”. (Do not start engine.)
5. Check voltage between combination meter harness connector terminal and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuse No. 14 located in the fuse block (J/B). Refer
to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

Harness for short or open between battery and combination meter harness connector M24 ter-
minal 24.

Ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .
Continuity should exist.
SDIA2691E
Connector
Terminal Voltage (Approx.)
M24 24 - Ground 0V
WDIA0151E
ConnectorTerminal Voltage (Approx.)
M24 24 - Ground Battery voltage
WDIA0152E

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

TF-122
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connec- tor E142 terminals 3, 6, E143 terminal 45 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK COMBINATION METER POWER SUPPLY CIRCUIT
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check voltage between combination meter harness connector terminal and ground.
4. Turn ignition switch “ ON”. (Do not start engine.)
5. Check voltage between combination meter harness connector terminal and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuse No. 14 located in the fuse block (J/B). Refer
to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

Harness for short or open between battery and combination meter harness connector M24 ter-
minal 24.

Ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .
Continuity should exist.
SDIA2691E
Connector
Terminal Voltage (Approx.)
M24 24 - Ground 0V
WDIA0151E
ConnectorTerminal Voltage (Approx.)
M24 24 - Ground Battery voltage
WDIA0152E

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-126
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: November 20092006 QX56
4. CHECK SYSTEM FOR ATP SWITCH
Perform trouble diagnosis for ATP switch system. Refer to TF-113, "
ATP Switch" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. 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 15 and
combination meter harness connector M24 terminal 6.
–Transfer control unit harness connector E142 terminal 40 and
combination meter harness connector M24 terminal 7.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6. CHECK ATP WARNING LAMP CIRCUIT
1. A/T selector lever in "P" position.
2. Connect combination meter harness connector and transfer control unit harness connector.
3. Disconnect ATP switch harness connector.
4. Ground the following terminal using suitable wiring.
–ATP switch harness connector F55 terminal 8 and ground.
5. Turn ignition switch “ ON”. (Do not start engine.)
Does indicator lamp turn on?
OK >> GO TO 7.
NG >> Replace combination meter. Refer to IP-13, "
COMBINA-
TION METER" .
Continuity should exist.
WDIA0149E
40 to 7: Continuity should not exist.
7 to 40: Continuity should exist.
WDIA0150E
SDIA2769E

TF-142
TRANSFER MOTOR
Revision: November 20092006 QX56
TRANSFER MOTORPFP:00000
Removal and InstallationEDS003BD
REMOVAL
1. Disconnect the transfer motor connector.
2. Remove the air breather hose from the transfer motor. Refer to
TF-139, "
Removal and Installation" .
3. Remove the transfer motor bolts.
4. Remove the transfer motor.
INSTALLATION
1. Apply ATF to the new O-ring and install it to the transfer motor.
CAUTION:
Do not reuse O-rings.
2. Fit the double-flat end of the transfer motor shaft into the slot of the sub-oil pump assembly. Then tighten to the specified torque.
Refer to TF-146, "
COMPONENTS" .
CAUTION:
Be sure to install connector bracket.
3. Install the air breather hose to the transfer motor. Refer to TF-
139, "Removal and Installation" .
4. Connect the transfer motor connector.
5. Check the transfer fluid. Refer to TF-11, "
FILLING" .
6. Start the engine for one minute. Then stop the engine and recheck the transfer fluid. Refer to TF-11,
"FLUID LEAKAGE AND FLUID LEVEL" .
SDIA2133E
SDIA2787E