2008 INFINITI QX56 engine

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]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
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]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
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

P1823 2-4 SOLENOIDDLN-57
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
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

P1824 TRANSFER MOTORDLN-61
< COMPONENT DIAGNOSIS > [ATX14B]
C
EF
G H
I
J
K L
M A
B
DLN
N
O P
P1824 TRANSFER MOTOR
DescriptionINFOID:0000000001737151
Motor does not operate properly due to open or short circuit in transfer motor or transfer motor relay.
DTC LogicINFOID:0000000001737152
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Perform self-diagnosis.
Is DTC P1824 displayed?
YES >> Perform diagnosis procedure. Refer to DLN-61, "Diagnosis Procedure".
NO >> Inspection End.
Diagnosis ProcedureINFOID:0000000001737153
1.CHECK TRANSFER MOTOR RELAY 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 MOTOR RELAY and MOTOR RELAY MON.
DTC CONSULT-III Diagnostic item is detected when... Reference
[P1824] MOTOR RELAY Motor does not operate properly due to
open or short circuit in transfer motor or
transfer motor relay.Refer to DLN-61
.
Monitored
item Condition Display value
(Approx.)
MOTOR
RELAY • Accelerator ped-
al depressed
• Vehicle stopped
• Engine running
• Brake pedal de- pressed 4WD shift switch: 2WD OFF
4WD shift switch: AUTO or
4LO (A/T selector lever P or N
position)
OFF
(ON for approx.
2 sec. after
shifting to P and
N.)
4WD shift switch: AUTO or
4LO (Except for A/T selector
lever P or N position) ON
4WD shift switch: 4H (A/T se-
lector lever P position) OFF
(ON for approx.
2 sec. after
shifting to P.)
4WD shift switch: 4H (Except
for A/T selector lever P posi-
tion) ON
Revision: March 2010
2008 QX56

DLN-62
< COMPONENT DIAGNOSIS >[ATX14B]
P1824 TRANSFER MOTOR

Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
MOTOR
RELAY
MON • Accelerator ped-
al depressed
• Vehicle stopped
• Engine running
• Brake pedal de- pressed 4WD shift switch: 2WD OFF
4WD shift switch: AUTO or
4LO (A/T selector lever P or N
position)
OFF
(ON for approx.
2 sec. after
shifting to P and
N.)
4WD shift switch: AUTO or
4LO (Except for A/T selector
lever P or N position) ON
4WD shift switch: 4H (A/T se-
lector lever P position) OFF
(ON for approx.
2 sec. after
shifting to P.)
4WD shift switch: 4H (Except
for A/T selector lever P posi-
tion) ON
Monitored
item Condition Display value
(Approx.)
Connector Terminal ConditionVoltage (Approx.)
E142 14 -
Ground • Accelera-
tor pedal
depressed
• Vehicle
stopped
•Engine running
•Brake pedal de-
pressed 4WD shift switch:
2WD
Battery voltage
4WD shift switch:
AUTO or 4LO (A/T
selector lever P or N
position) Battery voltage
(0V for approx. 2
sec. after shifting
to P and N.)
4WD shift switch:
AUTO or 4LO (Ex-
cept for A/T selector
lever P or N position) 0V
4WD shift switch: 4H
(A/T selector lever P
position) Battery voltage
(0V for approx. 2
sec. after shifting
to P.)
4WD shift switch: 4H
(Except for A/T se-
lector lever P posi-
tion) 0V
SDIA2735E
Revision: March 2010
2008 QX56