INFINITI QX56 2008 Factory Service Manual

P1827 CLUTCH PRESSURE SWITCHDLN-71
< COMPONENT DIAGNOSIS > [ATX14B]
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YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRAN SFER CONTROL UNIT AND CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 34 and transfer terminal cord assembly har-
ness connector F56 terminal 7
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 TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are inspection results normal?
YES >> GO TO 4.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with the harness connec-
tor. If any items are damaged, repair or replace damaged parts.
4.CHECK CLUTCH PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "
Component Parts Location".
3. Push and release clutch pressure switch and check continuity
between terminal 7 and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace clutch pressure switch.
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "
Preliminary Check".
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000001737162
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to DLN-16, "
Component Parts Location".
Continuity should exist.
SDIA2747E
Terminal
Condition Continuity
7 -
Ground Push clutch pressure switch
Yes
Release clutch pressure switch No
WDIA0171E
Revision: March 2010 2008 QX56

DLN-72
< COMPONENT DIAGNOSIS >[ATX14B]
P1827 CLUTCH PRESSURE SWITCH
3. Push and release clutch pressure switch and check continuity
between terminal 7 and ground.
4. If the inspection results are abnormal replace the clutch pres- sure switch.
Terminal Condition Continuity
7 - Ground Push clutch pressure switch
Yes
Release clutch pressure switch No
WDIA0171E
Revision: March 2010 2008 QX56

P1828 LINE PRESSURE SWITCHDLN-73
< COMPONENT DIAGNOSIS > [ATX14B]
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P1828 LINE PRESSURE SWITCH
DescriptionINFOID:0000000001737163
Improper signal from line pressure switch is input due to open or short circuit. Also, a malfunction may have
occured in the line pressure switch or hydraulic circuit.
DTC LogicINFOID:0000000001737164
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1828 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-73, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737165
1.CHECK LINE PRESSURE SWITCH SIGNAL
With CONSULT-III1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out ON/OFF switching action of LINE PRES SW while operating 4WD shift switch.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminals and ground.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1828] LINE PRES SW • Improper signal from line pressure
switch is input due to open or short cir-
cuit.
• Malfunction occurs in line pressure switch or hydraulic circuit. Refer to DLN-73
.
Condition
Display value
• A/T selector lever D position
• 4WD shift switch: AUTO ON
• Except the above
• The vehicle has been left at room temperature for 5
minutes and more with ig-
nition switch in OFF posi-
tion. • Ignition switch: ON
• A/T selector lever: P or N position
• 4WD shift switch: other than
AUTO OFF
SDIA2751E
Revision: March 2010
2008 QX56

DLN-74
< COMPONENT DIAGNOSIS >[ATX14B]
P1828 LINE PRESSURE SWITCH
Are inspection results normal?
YES >> GO TO 5.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN TRANSFER CONT
ROL UNIT AND LINE PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer terminal cord assembly harness con-
nector.
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 35 and transfer terminal cord assembly har-
ness connector F56 terminal 1.
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 TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are inspection results normal?
YES >> GO TO 4.
NO >> Check the following. If any items are damaged, repair or replace damaged parts. • Transfer control unit pin terminals for damage or loose connection with harness connector.
• Transfer control unit. Refer to DLN-128, "
Removal and Installation".
4.CHECK LINE PRESSURE SWITCH
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to DLN-16, "
Component Parts Location".
3. Push and release line pressure switch and check continuity between terminal 1 and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace line pressure switch.
5.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Connector Terminal ConditionVoltage
(Approx.)
E143 35 -
Ground • A/T selector lever D
position 4WD shift switch:
AUTO
0V
• Except the above
• The vehicle has been left at room
temperature for 5
minutes and more
with ignition switch
in OFF position. • Ignition switch:
ON
• A/T selector le-
ver: P or N posi-
tion
• 4WD shift
switch: other
than AUTO Battery
voltage
Continuity should exist.
SDIA2752E
Terminal
Condition Continuity
1 -
Ground Push line pressure switch
Yes
Release line pressure switch No
WDIA0172E
Revision: March 2010 2008 QX56

P1828 LINE PRESSURE SWITCHDLN-75
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Are inspection results normal?
YES >> GO TO 6.
NO >> Replace transfer control unit. Refer to DLN-128, "
Removal and Installation".
6.CRUISE TEST
Perform cruise test. Refer to DLN-7, "
Preliminary Check".
Are inspection results normal?
YES >> Inspection End.
NO >> Perform the applicable trouble diagnosis.
Component InspectionINFOID:0000000001737166
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to DLN-16, "
Component Parts Location".
3. Push and release line pressure switch and check continuity between terminal 1 and ground.
4. If the inspection results are abnormal, replace the line pressure switch.
Terminal Condition Continuity
1 - Ground Push line pressure switch
Yes
Release line pressure switch No
WDIA0172E
Revision: March 2010 2008 QX56

DLN-76
< COMPONENT DIAGNOSIS >[ATX14B]
P1829 THROTTLE POSITION SIGNAL (ECM)
P1829 THROTTLE POSITION SIGNAL (ECM)
DescriptionINFOID:0000000001737167
Malfunction is detected in accelerator pedal position si
gnal that is output from ECM through CAN communica-
tion. Also, the signal voltage from accelerator pedal position sensor may be abnormally high or low.
DTC LogicINFOID:0000000001737168
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1829 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-76, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737169
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 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
Perform the self-diagnosis, after driving a vehicle for a while.
Are inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ECM again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1829] THROTTLE POSI SEN • Malfunction is detected in accelerator
pedal position signal that is output
from ECM through CAN communica-
tion.
• Signal voltage from accelerator pedal position sensor is abnormally high or
low. Refer to
DLN-76
.
Revision: March 2010 2008 QX56

P1830 ABS OPERATION SIGNAL (ABS)DLN-77
< COMPONENT DIAGNOSIS > [ATX14B]
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P1830 ABS OPERATION SIGNAL (ABS)
DescriptionINFOID:0000000001737170
Malfunction is detected in ABS operation signal that is output from ABS actuator and electric unit (control unit)
through CAN communication.
DTC LogicINFOID:0000000001737171
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1830 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-77, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737172
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to BRC-24, "
CONSULT-III
Function (ABS)".
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 DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 3.
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.
3.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ABS actuator and electric unit (control unit) again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1830] ABS OP SIG Malfunction is detected in ABS operation
signal that is output from ABS actuator
and electric unit (control unit) through
CAN communication.Refer to DLN-77
.
Revision: March 2010
2008 QX56

DLN-78
< COMPONENT DIAGNOSIS >[ATX14B]
P1831 VDC OPERATION SIGNAL (ABS)
P1831 VDC OPERATION SIGNAL (ABS)
DescriptionINFOID:0000000001737173
Malfunction is detected in the VDC operation signal that
is output from ABS actuator and electric unit (control
unit) through CAN communication.
DTC LogicINFOID:0000000001737174
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1831 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-78, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737175
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT
Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to BRC-24, "
CONSULT-III
Function (ABS)".
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
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ABS act uator electric unit (control unit) again.
DTCCONSULT-III Diagnostic item is detected when... Reference
[P1831] VDC OP SIG Malfunction is detected in VDC opera-
tion signal that is
output from ABS actu-
ator and electric unit (control unit)
through CAN communication. Refer to
DLN-78
.
Revision: March 2010 2008 QX56

P1832 TCS OPERATION SIGNAL (ABS)DLN-79
< COMPONENT DIAGNOSIS > [ATX14B]
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P1832 TCS OPERATION SIGNAL (ABS)
DescriptionINFOID:0000000001737176
Malfunction is detected in TCS operation signal that is output from ABS actuator and electric unit (control unit)
through CAN communication.
DTC LogicINFOID:0000000001737177
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1832 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-79, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737178
1.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT
Perform self-diagnosis with ABS actuator and electric unit (control unit). Refer to BRC-24, "
CONSULT-III
Function (ABS)".
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 DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 3.
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.
3.CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
Are the inspection results normal?
YES >> Inspection End.
NO >> Perform self-diagnosis with ABS actuator electric unit (control unit) again.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1832] TCS OP SIG Malfunction is detected in TCS operation
signal that is output from ABS actuator
and electric unit (control unit) through
CAN communication.Refer to DLN-79
.
Revision: March 2010
2008 QX56

DLN-80
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
ECU DIAGNOSIS
TRANSFER CONTROL UNIT
Reference ValueINFOID:0000000001737179
VALUE ON THE DIAGNOSIS TOOL
CONSULT-III data monitor item
Monitored item [Unit]
Content ConditionDisplay value
VHCL/S SEN·FR [km/h]
or [mph] Wheel speed (Front
wheel) Vehicle stopped
0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
VHCL/S SEN·RR [km/h]
or [mph] Wheel speed (Rear
wheel) Vehicle stopped
0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
ENGINE SPEED [rpm] Engine speed Engine stopped
(Engine speed: Less than 400 rpm)
0 rpm
Engine running
(Engine speed: 400 rpm or more) Approximately
equal to the indica-
tion on tachometer
THRTL POS SEN [V] Accelerator
pedal posi-
tion (APP) sensor signal
voltage Accelerator pedal: Released
Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V] Transfer fluid tempera-
ture signal voltage Transfer fluid temperature approx. 20 - 80
°C (68 - 176 °F) Approx. 1.1 - 0.3V
BATTERY VOLT [V] Power supply voltage for
transfer control unit Ignition switch: ON
Battery voltage
2WD SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 2WD
ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: AUTO
ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: 4H
ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 4LO
ON
4WD shift switch: 2WD, AUTO or 4H OFF
N POSI SW TF [ON/
OFF] Condition of neutral-4LO
switch • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• 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
Revision: March 2010 2008 QX56