INFINITI QX56 2008 Factory Service Manual

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

DLN-54
< COMPONENT DIAGNOSIS >[ATX14B]
P1822 CLUTCH PRESSURE SOLENOID
Are the inspection results normal?
YES >> GO TO 7.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONT
ROL UNIT AND CLUTCH PRESSURE SOLENOID
VA LV E
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector, transfer terminal cord assembly harness connector
and transfer dropping resistor.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 19 and transfer terminal cord assembly har-
ness connector F56 terminal 6.
4. Check continuity between transfer dropping resistor harness connector E135 terminal 2 and transfer terminal cord assembly
harness connector F56 terminal 6.
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 HARNESS BETWEEN TRANSFER CONTRO L UNIT AND TRANSFER DROPPING RESISTOR
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer dropping resistor harness connector.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 10 and transfer dropping resistor harness con-
nector E135 terminal 1.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.CHECK GROUND CIRCUIT
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector. Continuity should exist.
SDIA2720E
Continuity should exist.
SDIA2721E
Continuity should exist.
SDIA2722E
Revision: March 2010
2008 QX56

P1822 CLUTCH PRESSURE SOLENOIDDLN-55
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3. Check continuity between transfer terminal cord assembly har- ness connector F56 terminal 19 and ground.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 5.
NO >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK CLUTCH PRESSURE SOLENOID
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly har- ness connector F56 terminals 6 and 19.
Are the inspection results normal?
YES >> GO TO 6.
NO >> Replace clutch pressure solenoid. Refer to DLN-16,
"Component Parts Location".
6.CHECK 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.
Are the inspection results normal?
YES >> GO TO 7.
NO >> Replace transfer dropping resistor.
7.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 8.
NO >> Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
8.CHECK DTC
Drive the vehicle and then perform self-diagnosis.
Are the inspection results normal?
YES >> Inspection End.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
Component InspectionINFOID:0000000001737146
CLUTCH PRESSURE SOLENOID
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)Continuity should exist.
SDIA2723E
6 - 19 : Approx. 3.0 - 3.4
Ω
SDIA2724E
1 - 2 : Approx. 11.2 - 12.8 Ω
SDIA2725E
Revision: March 2010 2008 QX56

DLN-56
< COMPONENT DIAGNOSIS >[ATX14B]
P1822 CLUTCH PRESSURE SOLENOID
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter-
minals 6 and 19.
4. If the inspection results are abnormal replace clutch pressure solenoid. Refer to DLN-16, "
Component Parts Location".
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 the inspection results are abnormal replace transfer dropping resistor. Refer to DLN-16, "
Component Parts Location".
6 - 19 : Approx. 3.0 - 3.4
Ω
WDIA0225E
1 - 2 : Approx. 11.2 - 12.8 Ω
SDIA2725E
Revision: March 2010 2008 QX56

P1823 2-4 SOLENOIDDLN-57
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P1823 2-4 SOLENOID
DescriptionINFOID:0000000001737147
Proper voltage is not applied to the 2-4WD solenoid valve due to an open or short circuit.
DTC LogicINFOID:0000000001737148
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1823 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-57, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737149
1.CHECK 4WD SHIF T SWITCH SYSTEM
Perform self-diagnosis. Refer to DLN-18, "
CONSULT-III Function (ALL MODE AWD/4WD)".
Is the 4WD MOD SW [P1814] (with CO NSULT-III) or Flickering pattern: 16 (without CONSULT-III) detected?
YES >> Perform trouble diagnosis for 4WD shift switch. Refer to DLN-31, "Diagnosis Procedure".
NO >> GO TO 2.
2.CHECK 2-4WD SHIFT SOLENOID 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 2-4WD SOL and 2-4WD SOL MON.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1823] 2-4WD SOLENOID Proper voltage is not applied to 2-4WD
solenoid valve due to open or short cir-
cuit.Refer to DLN-57
.
Monitored
item Condition Display
value
2-4WD SOL • Vehicle stopped
• Engine running
• A/T selector lever N
position
• Brake pedal de- pressed 4WD 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
Revision: March 2010
2008 QX56

DLN-58
< COMPONENT DIAGNOSIS >[ATX14B]
P1823 2-4 SOLENOID

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 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.
Are the inspection results normal?
YES >> GO TO 4.
NO >> Check 4WD shift switch. Refer to DLN-33, "
Component Inspection".
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.
2-4WD SOL
MON • Vehicle stopped
• Engine running
• A/T selector lever N
position
• Brake pedal de- pressed 4WD 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
Monitored
item Condition Display
value
Connector Terminal ConditionVoltage
(Approx.)
E142 1 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch: 2WD 0V
4WD shift switch: AU-
TO, 4H or 4LO
Battery
voltage
SDIA2728E
Connector Terminal
ConditionVoltage (Ap-
prox.)
M141 4 - ground 4WD shift switch: AUTO, 4H or 4LO Battery voltage
4WD shift switch: 2WD
0V
SDIA2729E
Revision: March 2010 2008 QX56

P1823 2-4 SOLENOIDDLN-59
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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.
Are the inspection results normal?
YES >> GO TO 5.
NO >> Repair or replace damaged parts.
5.CHECK HARNESS BETWEEN TRANSF ER CONTROL UNIT AND TRANSFER TERMINAL CORD AS-
SEMBLY
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit har ness connector and transfer terminal cord assembly harness connec-
tor.
3. Check continuity between transfer control unit harness connec- tor E142 terminal 1 and transfer terminal cord assembly harness
connector F56 terminal 4.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 6.
NO >> Repair or replace damaged parts.
6.CHECK 2-4WD SOLENOID
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 4 and 5.
Are the inspection results normal?
YES >> GO TO 7.
NO >> Replace 2-4WD solenoid. Refer to DLN-16, "
Compo-
nent Parts Location".
7.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 8.
NO >> Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
8.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
Continuity should exist.
SDIA2731E
Continuity should exist.
SDIA2732E
4 - 5 : Approx. 22.8 - 25.2
Ω
WDIA0187E
Revision: March 2010 2008 QX56

DLN-60
< COMPONENT DIAGNOSIS >[ATX14B]
P1823 2-4 SOLENOID
Component Inspection
INFOID:0000000001737150
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer terminal cord assembly harness connector.
3. Check resistance between transfer terminal cord assembly ter- minals 4 and 5.
4. If the inspection results are abnormal replace the 2-4WD sole- noid. Refer to DLN-16, "
Component Parts Location".
4 - 5 : Approx. 22.8 - 25.2 Ω
WDIA0187E
Revision: March 2010
2008 QX56