2009 INFINITI QX56 check engine

DLN-22
< COMPONENT DIAGNOSIS >[ATX14B]
P1811 POWER SUPPLY CIRCUIT
FOR TRANSFER CONTROL UNIT
COMPONENT DIAGNOSIS
P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT
DescriptionINFOID:0000000003772080
Power supply to transfer control unit is abnormally low while driving.
DTC LogicINFOID:0000000003772081
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1811 detected?
YES >> Perform diagnosis procedure. Refer to DLN-22, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772082
1.CHECK POWER SUPPLY
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.
Are the inspection results normal?
YES >> GO TO 2.
NO >> Check the following. If any items are damaged, repair or replace damaged parts.
DTC CONSULT-III Diagnostic item is detected when... Reference
[ P 1 8 11 ] B AT T E R Y V O LTA G E Power supply voltage for transfer control
unit is abnormally low while driving.Refer to
DLN-22
.
Connector Terminal 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
Revision: December 20092009 QX56

DLN-28
< COMPONENT DIAGNOSIS >[ATX14B]
P1810 NEUTRAL-4LO SWITCH
P1810 NEUTRAL-4LO SWITCH
DescriptionINFOID:0000000003772093
The neutral-4LO switch detects that the transfer case
is in neutral or 4LO range. DTC P1810 will set when an
improper signal from the neutral-4LO switch is input due to an open or short circuit.
DTC LogicINFOID:0000000003772094
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1810 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-28, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772095
1.CHECK 4LO POSITION SWITCH SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for A LL MODE AWD/4WD with CONSULT-III.
3. Read out the value of N POSI SW TF.
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
[P1810] 4L POSI SW TF Improper signal from neutral-4LO switch
is input due to open or short circuit.Refer to
DLN-28
.
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 mo-
tor is operating.) OFF
→ ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→ OFF
4WD shift switch: 4LO ON
SDIA2693E
Revision: December 20092009 QX56

P1810 NEUTRAL-4LO SWITCHDLN-29
< COMPONENT DIAGNOSIS > [ATX14B]
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DLN
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Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TR ANSFER CONTROL UNIT AND NEUTRAL-4LO SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connecto r and the neutral-4LO switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 25 and neutral-4LO switch harness connector
F60 terminal 13.
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 neutral-4LO switch harness connector.
3. Check continuity between neutral-4LO switch harness connec- tor F60 terminal 12 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 4LO SWITCH
1. Turn ignition switch OFF.
2. Disconnect neutral-4LO switch harness connector.
3. Remove neutral-4LO switch.
Connector Te r m i n a l
(Wire col-
or) Condition
Voltage
(Approx.)
E143 25 -
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.
SDIA2694E
Continuity should exist.
SDIA2695E
Revision: December 20092009 QX56

P1813 4WD SHIFT SWITCHDLN-31
< COMPONENT DIAGNOSIS > [ATX14B]
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DLN
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P1813 4WD SHIFT SWITCH
DescriptionINFOID:0000000003772097
The 4WD shift switch allows the driver to select AUTO, 2WD or 4WD and 4H or 4LO. DTC P1813 will set if
more than two switch inputs are simultaneously detected by the transfer control unit due to a short circuit in the
4WD shift switch.
DTC LogicINFOID:0000000003772098
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1813 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-31, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000003772099
1.CHECK 4WD SHIFT SWITCH SIGNAL
With CONSULT-III
1. Turn ignition switch ON. (Do not start engine.)
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out ON/OFF switching action of the 2WD SWITCH, AUTO SWITCH, LOCK SWITCH, 4L SW with
operating 4WD shift switch.
Without CONSULT-III
1. Turn ignition switch ON. (Do not start engine.)
2. Check voltage between transfer control unit harness connector
terminals and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1813] 4WD MODE SW More than two switch inputs are simulta-
neously detected due to short circuit of
4WD shift switch.Refer to
DLN-31
.
Connector Terminal Condition Voltage (Ap-
prox.)
E142 9 - ground
4WD shift switch: 2WD Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 - ground 4WD shift switch: 4H Battery voltage
4WD shift switch: 2WD, AUTO or
4LO
0V
23 - ground 4WD shift switch: 4LO Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 - ground 4WD shift switch: AUTO Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V
WDIA0148E
Revision: December 20092009 QX56

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 5.
 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
Connector Terminal Voltage (Approx.) M141 1 - Ground Battery voltage
PDIA0210E
Continuity should exist.SDIA2699E
Revision: December 20092009 QX56

P1814 WAIT DETECTION SWITCHDLN-35
< COMPONENT DIAGNOSIS > [ATX14B]
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M A
B
DLN
N
O P
P1814 WAIT DETECTION SWITCH
DescriptionINFOID:0000000003772101
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:0000000003772102
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:0000000003772103
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: December 20092009 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 Terminal Condition Voltage
(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: December 20092009 QX56

P1817 ACTUATOR MOTORDLN-39
< COMPONENT DIAGNOSIS > [ATX14B]
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P1817 ACTUATOR MOTOR
DescriptionINFOID:0000000003772108
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:0000000003772109
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:0000000003772110
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: December 20092009 QX56