2007 INFINITI QX56 check engine

TF-74
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
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 fuse No. 26 located in the fuse and fusible link box. Refer to PG-3
.
• Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1.
• Harness for short or open between transfer shut off relay harness connector E69 terminal 2 and
transfer control unit harness connector E143 terminal 30.
• Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 3.
• Harness for short or open between transfer shut off relay harness connector E69 terminal 5 and
transfer control unit harness connector E142 terminal 22.
• Transfer shut off relay. Refer to TF-51, "
Power Supply Circuit for Transfer Control Unit".
2.CHECK 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 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. Refer to TF-22, "
Location of Electrical Parts".
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.
Connector Terminal Voltage (Approx.)
E14216 - Ground
Battery voltage
22 - Ground
E143 30 - Ground 0V
SDIA2835E
Continuity should exist.
SDIA2691E
Connector Terminal Voltage (Approx.)
E46 5 - Ground
Battery voltage
E47 5 - Ground
WDIA0310E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-75
< SERVICE INFORMATION >
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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 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.
• 20A fuse No. 57 located in the fuse and relay box. Refer to PG-3
.
• Harness for short or open between battery, transfer shift high relay harness connector E46 ter-
minal 5 and transfer shift low relay harness connector E47 terminal 5.
4.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER SHIFT RELAY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer control device (actuator motor) harness
connector.
3. Remove transfer shift high relay and transfer shift low relay. Refer to TF-22, "
Location of Electrical Parts".
4. Check continuity between the following terminals.
- Transfer control unit harness connector E143 terminal 33 (A)
and transfer shift high relay harness connector E46 terminal 3
(B).
- Transfer control unit harness connector E143 terminal 42 (A)
and transfer shift low relay harness connector E47 terminal 3
(C).
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 TRANSFER SHIFT RELAY GROUND 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 continuity between transfer shift high relay harness con-
nector E46 terminals 2, 4 (A), transfer shift low relay harness
connector E47 terminals 2, 4 (B) and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
6.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-1 >> With CONSULT-II: GO TO 7.
OK-2 >> Without CONSULT-II: GO TO 8.
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.
Connector Terminal Voltage (Approx.)
E46 5 - Ground
Battery voltage
E47 5 - Ground
WDIA0311E
Continuity should exist.
WDIA0315E
Continuity should exist.
WDIA0312E

TF-76
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
7.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
“SHIFT ACT CIR [P1819]” displayed?
YES >> Replace transfer control unit. Refer to TF-115, "Removal and Installation".
NO >> Inspection End.
8.PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-II)
Without CONSULT-II1. 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 transfer control device?
YES >> Replace transfer control unit. Refer to TF-121, "Removal and Installation".
NO >> Inspection End.
Engine Speed Signal (ECM)INFOID:0000000003532540
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 E C - 111 , "
CONSULT-II Function (ENGINE)" .
Clutch Pressure SolenoidINFOID:0000000003532541
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
DUTY SOLENOID [%]Condition of clutch pres-
sure solenoid• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal depressed4WD shift switch: 2WD 4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO4%

TROUBLE DIAGNOSIS FOR SYSTEM
TF-77
< SERVICE INFORMATION >
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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 CLUTCH PRESSURE SIGNAL
With CONSULT-II1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Read out the value of “DUTY SOLENOID”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
Te r m i n a lWire
colorItem Condition Data (Approx.)
10 L/W Transfer dropping resistor• Vehicle stopped
• Engine running
• A/T selector le-
ver “N” position
• Brake pedal de-
pressed4WD shift switch: AUTO 4 - 14V
4WD shift switch: 2WD, 4H or 4LO Less than 1V
19 LClutch pressure solenoid
valve• Vehicle stopped
• Engine running
• A/T selector le-
ver “N” position
• Brake pedal de-
pressed4WD shift switch: AUTO 1.5 - 3V
4WD shift switch: 2WD, 4H or 4LO Less than 1V
Condition Display value
• Vehicle stopped
• Engine running
• A/T selector lever “N” position
• Brake pedal depressed4WD shift switch: 2WD 4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO4%
SDIA2718E
Connector Terminal ConditionVoltage
(Approx.)
E142 10 -
Ground• Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de-
pressed4WD shift switch:
AUTO4 - 14V
4WD shift switch:
2WD, 4H or 4LOLess than
1V
19 -
Ground• Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de-
pressed4WD shift switch:
AUTO1.5 - 3V
4WD shift switch:
2WD, 4H or 4LOLess than
1V
SDIA2719E

TF-80
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
3. Check resistance between transfer terminal cord assembly ter-
minals 6 and 19.
4. If NG, replace clutch pressure solenoid. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Dropping Resistor
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer dropping resistor harness connector.
3. Check resistance between transfer dropping resistor terminals 1
and 2.
4. If NG, replace transfer dropping resistor. Refer to TF-22, "
Loca-
tion of Electrical Parts".
2-4WD SolenoidINFOID:0000000003532542
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
6 - 19 : Approx. 3.0 - 3.4 Ω
WDIA0225E
1 - 2 : Approx. 11.2 - 12.8 Ω
SDIA2725E
Monitored item Content Condition Display value
2-4WD SOL [ON/OFF]Condition of 2-4WD shift
solenoid valve• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal depressed4WD 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
2-4WD SOL MON [ON/
OFF]Check signal for transfer
control unit signal output• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal depressed4WD 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

TROUBLE DIAGNOSIS FOR SYSTEM
TF-81
< SERVICE INFORMATION >
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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 SYSTEM
Perform self-diagnosis. Refer to TF-48, "
Self-Diagnosis Procedure".
Is the "4WD MOD SW [P1814]" (with CONSULT-II) or "Flickering pattern: 16 (without CONSULT-II) detected?
YES >> Perform trouble diagnosis for 4WD shift switch. Refer to TF-57, "4WD Shift Switch".
NO >> GO TO 2.
2.CHECK 2-4WD SHIFT SOLENOID 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 “2-4WD SOL” and “2-4WD SOL MON”.
Without CONSULT-II
1. Start engine.
Te r m i n a lWire
colorItem Condition Data (Approx.)
1 GR 2-4WD shift solenoid valve• Vehicle stopped
• Engine running
• A/T selector le-
ver “N” position
• Brake pedal de-
pressed4WD shift switch: 2WD 0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
Monitored
itemConditionDisplay
value
2-4WD SOL• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal de-
pressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON 4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(“Wait” function is operating.)OFF
4WD shift switch: 4H (“Wait”
function is operating.)OFF
2-4WD SOL
MON• Vehicle stopped
• Engine running
• A/T selector lever “N”
position
• Brake pedal de-
pressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
ON 4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(“Wait” function is operating.)OFF
4WD shift switch: 4H (“Wait”
function is operating.)OFF
SDIA2727E

TF-82
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
2. Check voltage between transfer control unit harness connector
terminal and ground.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
3.CHECK 4WD SHIFT SWITCH SIGNAL
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 4.
NG >> Check 4WD shift switch. Refer to TF-57, "
4WD Shift Switch".
4.CHECK HARNESS BETWEEN 4WD SHIFT SWITCH AND TRANSFER TERMINAL CORD ASSEMBLY
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector and transfer terminal cord assembly harness connector.
3. Check continuity between 4WD shift switch harness connector
M141 terminal 4 and transfer terminal cord assembly harness
connector F56 terminal 5.
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 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.
Connector Terminal ConditionVoltage
(Approx.)
E142 1 -
Ground• Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de-
pressed4WD shift switch: 2WD 0V
4WD shift switch: AU-
TO, 4H or 4LOBattery
voltage
SDIA2728E
Connector Terminal ConditionVoltage (Ap-
prox.)
M141 4 - ground4WD shift switch: AUTO, 4H or 4LO Battery voltage
4WD shift switch: 2WD 0V
SDIA2729E
Continuity should exist.
SDIA2731E

TF-84
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS FOR SYSTEM
Transfer Motor
INFOID:0000000003532543
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.
Monitored item Content Condition Display value
MOTOR RELAY [ON/
OFF]Condition of transfer motor
relay• Accelerator pedal de-
pressed
• Vehicle stopped
• Engine running
• Brake pedal depressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
“P” or “N” position)OFF
("ON" for approx. 2
sec. after shifting to
“P” and “N”.)
4WD shift switch: AUTO
or 4LO (Except for A/T se-
lector lever “P” or “N” posi-
tion)ON
4WD shift switch: 4H (A/T
selector lever “P” position)OFF
("ON" for approx. 2
sec. after shifting to
“P”.)
4WD shift switch: 4H (Ex-
cept for A/T selector lever
“P” position)ON
MOTOR RELAY MON
[ON/OFF]Check signal for transfer
control unit signal output• Accelerator pedal de-
pressed
• Vehicle stopped
• Engine running
• Brake pedal depressed4WD shift switch: 2WD OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
“P” or “N” position)OFF
("ON" for approx. 2
sec. after shifting to
“P” and “N”.)
4WD shift switch: AUTO
or 4LO (Except for A/T se-
lector lever “P” or “N” posi-
tion)ON
4WD shift switch: 4H (A/T
selector lever “P” position)OFF
("ON" for approx. 2
sec. after shifting to
“P”.)
4WD shift switch: 4H (Ex-
cept for A/T selector lever
“P” position)ON
Te r m i n a lWire
colorItem Condition Data (Approx.)
14 LG Transfer motor relay• Accelerator ped-
al depressed
• Vehicle stopped
• Engine running
• Brake pedal de-
pressed4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO or 4LO (A/T selec-
tor lever “P” or “N” position)Battery voltage
(0V for approx.
2 sec. after
shifting to “P”
and “N”.)
4WD shift switch: AUTO or 4LO (Except for
A/T selector lever “P” or “N” position)0V
4WD shift switch: 4H (A/T selector lever
“P” position)Battery voltage
(0V for approx.
2 sec. after
shifting to “P”.)
4WD shift switch: 4H (Except for A/T selec-
tor lever “P” position)0V