2008 INFINITI QX56 ignition

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

DLN-48
< COMPONENT DIAGNOSIS >[ATX14B]
P1819 TRANSFER CONTROL DEVICE
P1819 TRANSFER CONTROL DEVICE
DescriptionINFOID:0000000001737137
The transfer control device integrates the actuator motor and actuator pos
ition switch. DTC P1819 will set if
either of the following conditions exist:
• Malfunction occurs in transfer control device actuator circuit.
• Malfunction is detected in the transfer shut off relay.
DTC LogicINFOID:0000000001737138
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1819 detected?
YES >> Perform diagnosis procedure. Refer to DLN-48, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737139
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 terminal and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1819] SHIFT ACT CIR • Transfer control device actuator circuit
is shorted or open. (Malfunctions are
detected when transfer shift relay cir-
cuit is open/shorted or relay monitor
circuit is open/shorted.)
• Malfunction occurs in transfer control device drive circuit.
• Malfunction is detected in transfer shut off relay. Refer to
DLN-48
.
Connector Terminal Voltage (Approx.)
E142 16 - Ground
0V
22 - Ground
E143 30 - Ground Battery voltage
SDIA2834E
Revision: March 2010 2008 QX56

P1819 TRANSFER CONTROL DEVICEDLN-49
< COMPONENT DIAGNOSIS > [ATX14B]
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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. • 10A fuse (No. 26 located in the fuse and fusible link box).
• 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 DLN-23, "
Component Inspection".
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.
Are the inspection results normal?
YES >> GO TO 3.
NO >> 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 DLN-16, "
Component Parts Loca-
tion".
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.)
E142 16 - Ground
Battery voltage
22 - Ground
E143 30 - Ground 0V
SDIA2835E
Continuity should exist.
SDIA2691E
ConnectorTerminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0310E
Revision: March 2010 2008 QX56

DLN-50
< COMPONENT DIAGNOSIS >[ATX14B]
P1819 TRANSFER CONTROL DEVICE
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 4.
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 E46 ter-minal 5 and transfer shift low relay harness connector E47 terminal 5.
4.CHECK HARNESS BETWEEN TRANSFER CONT ROL 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.
4. Check continuity between the following terminals.
- Transfer control unit harness connector E143 terminal 33 and transfer shift high relay harness connector E46 terminal 3.
- Transfer control unit harness connector E143 terminal 42 and
transfer shift low relay harness connector E47 terminal 3.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 5.
NO >> 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, transfer shift low relay harness con-
nector E47 terminals 2, 4 and ground.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 6.
NO >> 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 DLN-80, "
Reference Value".
Are the inspection results normal?
YES-1 >> With CONSULT-III: GO TO 7.
YES-2 >> Without CONSULT-III: GO TO 8.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
7.PERFORM SELF-DIAGNOSIS (WITH CONSULT-III)
Connector Terminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0311E
Continuity should exist.
WDIA0315E
Continuity should exist.
WDIA0312E
Revision: March 2010 2008 QX56

P1819 TRANSFER CONTROL DEVICEDLN-51
< COMPONENT DIAGNOSIS > [ATX14B]
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With CONSULT-III
1. Turn ignition switch ON. (Do not start engine.)
2. Select SELF-DIAG RESULTS mode for ALL MODE AWD/4WD with CONSULT-III.
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 DLN-128, "Removal and Installation".
NO >> Inspection End.
8.PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-III)
Without CONSULT-III
1. Perform the self-diagnosis and then eras e self-diagnostic results. Refer to DLN-18, "CONSULT-III Func-
tion (ALL MODE AWD/4WD)".
2. Perform the self-diagnosis again.
Do the self-diagnostic results indicate transfer control device?
YES >> Replace transfer control unit.
NO >> Inspection End.
Revision: March 2010 2008 QX56

DLN-52
< COMPONENT DIAGNOSIS >[ATX14B]
P1820 ENGINE SPEED SIGNAL
P1820 ENGINE SPEED SIGNAL
DescriptionINFOID:0000000001737140
The ECM transmits the engine speed signal via CAN comm
unication to the transfer control unit. DTC P1820
will set when either of the following occur:
• Malfunction is detected in engine speed signal that is output from the ECM.
• Improper signal is input while driving.
DTC LogicINFOID:0000000001737141
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1820 detected?
YES >> Perform diagnosis procedure. Refer to DLN-52, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737142
1.CHECK DTC WITH ECM
Perform self-diagnosis with ECM. Refer to EC-63, "
CONSULT-III Function (ENGINE)".
Is any malfunction detec ted 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 DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
3.CHECK DTC
Drive the vehicle and then perform self-diagnosis.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ECM again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1820] ENGINE SPEED SIG • Malfunction is detected in engine
speed signal that is output from ECM
through CAN communication.
• Improper signal is input while driving. Refer to
DLN-52
.
Revision: March 2010 2008 QX56

P1822 CLUTCH PRESSURE SOLENOIDDLN-53
< COMPONENT DIAGNOSIS > [ATX14B]
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P1822 CLUTCH PRESSURE SOLENOID
DescriptionINFOID:0000000001737143
Proper voltage is not applied to the clutch pressure solenoid valve due to open or short circuit.
DTC LogicINFOID:0000000001737144
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1822 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-53, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737145
1.CHECK CLUTCH PRESSURE SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of DUTY SOLENOID.
Without CONSULT-III1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1822] DUTY SOLENOID Proper voltage is not applied to clutch
pressure solenoid valve due to open or
short circuit.Refer to DLN-53
.
Condition
Display value
• Vehicle stopped
• Engine running
• A/T selector lever N position
• Brake pedal depressed 4WD shift switch: 2WD
4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO 4%
Connector Terminal
ConditionVoltage
(Approx.)
E142 10 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch:
AUTO
4 - 14V
4WD shift switch:
2WD, 4H or 4LO Less than
1V
19 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch:
AUTO
1.5 - 3V
4WD shift switch:
2WD, 4H or 4LO Less than
1V
SDIA2719E
Revision: March 2010
2008 QX56