2008 INFINITI QX56 check engine

DLN-32
< COMPONENT DIAGNOSIS >[ATX14B]
P1813 4WD SHIFT SWITCH
2.CHECK 4WD SHIFT SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
3. Check voltage between 4WD shift switch harness connector ter- minal 1 and ground.
4. Turn ignition switch ON. (Do not start engine.)
5. Check voltage between 4WD shift switch harness connector ter- minal 1 and ground.
Are inspection results normal?
YES >> GO TO 3.
NO >> Refer to DLN-22, "
Diagnosis Procedure".
3.CHECK HARNESS BETWEEN 4WD SHIFT SWITCH AND TRANSFER CONTROL UNIT
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the 4WD shift switch harness connector.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E142 terminal 9 and 4WD shift switch harness connector M141 terminal 2.
- Transfer control unit harness connector E142 terminal 18 and 4WD shift switch harness connector M141 terminal 5.
- Transfer control unit harness connector E142 terminal 23 and 4WD shift switch harness connector M141 terminal 6.
- Transfer control unit harness connector E142 terminal 24 and
4WD shift switch harness connector M141 terminal 3.
Also check harness for short to ground and short to power.
Are inspection results normal?
YES >> GO TO 4.
NO >> Check the following. If any items are damaged, repair or replace damaged parts. • Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 3.
• Power supply circuit for transfer control unit. Refer to DLN-22, "
Diagnosis Procedure".
4.CHECK 4WD SHIFT SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect 4WD shift switch harness connector.
Connector Terminal Voltage (Approx.)
M141 1 - Ground 0V
SDIA2383E
ConnectorTerminal Voltage (Approx.)
M141 1 - Ground Battery voltage
PDIA0210E
Continuity should exist.SDIA2699E
Revision: March 2010 2008 QX56

P1814 WAIT DETECTION SWITCHDLN-35
< COMPONENT DIAGNOSIS > [ATX14B]
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P1814 WAIT DETECTION SWITCH
DescriptionINFOID:0000000001737122
The wait detection switch detects if the transfer case is in 4WD. DTC P1814 will set if an improper signal from
the wait detection switch is input due to open or short circuit.
DTC LogicINFOID:0000000001737123
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1814 detected?
YES >> Perform diagnosis procedure. Refer to DLN-35, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737124
1.CHECK WAIT DETECTION SWITCH SIGNAL
With CONSULT-III
1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of WAIT DETCT SW.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1814] 4WD DETECT SWITCH Improper signal from wait detection
switch is input due to open or short cir-
cuit.
Refer to DLN-35
.
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
SDIA2701E
Revision: March 2010 2008 QX56

DLN-36
< COMPONENT DIAGNOSIS >[ATX14B]
P1814 WAIT DETECTION SWITCH
Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONT
ROL 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.
Are inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
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.
Are inspection results normal?
YES >> GO TO 4.
NO >> 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 DLN-16, "
Component Parts Location".
Connector TerminalConditionVoltage
(Approx.)
E143 43 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 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
Continuity should exist.
SDIA2702E
Continuity should exist.
SDIA2703E
Revision: March 2010 2008 QX56

P1817 ACTUATOR MOTORDLN-39
< COMPONENT DIAGNOSIS > [ATX14B]
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P1817 ACTUATOR MOTOR
DescriptionINFOID:0000000001737129
The actuator motor receives signals from the transfer c ontrol unit and controls shift rods which shift the trans-
fer case. DTC P1817 will set when any of the following occur:
• Motor does not operate properly due to open or short circuit in actuator motor.
• Malfunction is detected in the actuator motor. (W hen 4WD shift switch is operated and actuator motor does
not operate)
• Malfunction is detected in transfer shift high relay or transfer shift low relay.
DTC LogicINFOID:0000000001737130
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1817 detected?
YES >> Perform diagnosis procedure. Refer to DLN-39, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737131
1.CHECK ACTUATOR MOTOR SIGNAL
With CONSULT-III
1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of SHIFT ACT1, SHIFT AC MON1, SHIFT ACT2 and SHIFT AC MON2.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1817] SHIFT ACTUATOR • Motor does not operate properly due
to open or short circuit in actuator mo-
tor.
• Malfunction is detected in the actuator motor. (When 4WD shift switch is op-
erated and actuator motor is not oper-
ated)
• Malfunction is detected in transfer shift
high relay and transfer shift low relay. Refer to DLN-39
.
Monitored
item Condition Display
value
SHIFT ACT1 • Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch: 4H
to 4LO (Wait function
is operating.)
ON
Except the above OFF
SHIFT AC
MON1 • Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch: 4H
to 4LO (Wait function
is operating.)
ON
Except the above OFF
SHIFT ACT2 • Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch:
4LO to 4H (Wait func-
tion is operating.)
ON
Except the above OFF
Revision: March 2010 2008 QX56

DLN-40
< COMPONENT DIAGNOSIS >[ATX14B]
P1817 ACTUATOR MOTOR

Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
Are the inspection results normal?
YES >> GO TO 7.
NO >> 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.
SHIFT AC
MON2 • Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch:
4LO to 4H (Wait func-
tion is operating.)
ON
Except the above OFF
Connector Terminal ConditionVoltage
(Approx.)
E142 4 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch: 4H to
4LO (Wait function is
operating.)
Battery
voltage
Except the above 0V
13 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch: 4LO
to 4H (Wait function is
operating.)
Battery
voltage
Except the above 0V
E143 33 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 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 de-
pressed 4WD shift switch: 4LO
to 4H (Wait function is
operating.)
Battery
voltage
Except the above 0V
Monitored
item Condition Display
value
SDIA2705E
Connector Terminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0310E
Revision: March 2010 2008 QX56

P1817 ACTUATOR MOTORDLN-41
< COMPONENT DIAGNOSIS > [ATX14B]
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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.
Are the inspection results normal?
YES >> GO TO 3.
NO >> Check the following. If any items are damaged, repair or replace damaged parts. • 20A fuse (No. 57, located in the fuse and relay box).
• Harness for short or open between battery, transfer shift high relay harness connector terminal 5and transfer shift low relay harness connector terminal 5.
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 DLN-16, "
Component Parts Loca-
tion".
3. Check continuity between transfer shift high relay harness con- nector E46 terminals 2, 4 (A) and transfer shift low relay harness
connector E47 terminals 2, 4 (B) and ground.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 4.
NO >> 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 DLN-16, "
Component Parts Loca-
tion".
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.
Are the inspection results normal?
YES >> GO TO 5.
NO >> Replace the transfer shut off relay. Refer to DLN-16, "
Component Parts Location".
5.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 the transfer control device (actuator motor) har-
ness connector.
3. Remove transfer shift high relay and transfer shift low relay.
4. Check continuity between the following terminals.
Connector Terminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0311E
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
Revision: March 2010 2008 QX56

P1818 ACTUATOR POSITION SWITCHDLN-45
< COMPONENT DIAGNOSIS > [ATX14B]
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P1818 ACTUATOR POSITION SWITCH
DescriptionINFOID:0000000001737133
The actuator position switch detects the current actuator motor range. DT C P1818 will set if either of the fol-
lowing occur:
• Improper signal from actuator position s witch is input due to open or short circuit.
• Malfunction is detected in actuator position switch.
DTC LogicINFOID:0000000001737134
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1818 detected?
YES >> Perform diagnosis procedure. Refer to DLN-45, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737135
1.CHECK ACTUATOR POSITION SWITCH SIGNAL
With CONSULT-III
1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of SHIFT POS SW1 and SHIFT POS SW2.
Without CONSULT-III
1. Start engine.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1818] SHIFT ACT POSI SW • Improper signal from actuator position
switch is input due to open or short cir-
cuit.
• Malfunction is detected in the actuator
position switch. Refer to DLN-45
.
Monitored item
ConditionDisplay value
SHIFT POS SW1 • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch: 4LO ON
4WD shift switch:
2WD, AUTO or 4H
OFF
SHIFT POS SW2 • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch: 4H,
AUTO or 2WD
ON
4WD shift switch: 4LO OFF
Revision: March 2010 2008 QX56

DLN-46
< COMPONENT DIAGNOSIS >[ATX14B]
P1818 ACTUATOR POSITION SWITCH
2. Check voltage between transfer control unit harness connector
terminal and ground.
Are the inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONTRO L UNIT AND ACTUATOR POSITION SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer control device (actuator position
switch) harness connector.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E143 terminal 27 and transfer control device (actuator position switch) harness con-
nector F58 terminal 23.
- Transfer control unit harness connector E143 terminal 44 and
transfer control device (actuator position switch) harness con-
nector F58 terminal 20.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK GROUND CIRCUIT
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control device (act uator position switch) harness connector.
3. Check continuity between transfe r control device (actuator posi-
tion switch) harness connector F58 terminal 22 and ground.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK ACTUATOR POSITION SWITCH
1. Remove transfer control device. Refer to DLN-134, "
Removal and Installation".
Connector TerminalConditionVoltage
(Approx.)
E143 27 -
Ground • Vehicle stopped
• Engine running
• A/T selector le-
ver N position
• Brake pedal de- pressed 4WD shift switch: 4H,
AUTO or 2WD
0V
4WD shift switch: 4LO Battery
voltage
44 -
Ground • Vehicle stopped
• Engine running
• A/T selector le-
ver N position
• Brake pedal de- pressed 4WD shift switch: 4LO 0V
4WD shift switch:
2WD, AUTO or 4H
Battery
voltage
SDIA2715E
Continuity should exist.
SDIA2716E
Continuity should exist.
SDIA2717E
Revision: March 2010
2008 QX56