battery voltage INFINITI QX56 2008 Factory Service Manual

DLN-22
< COMPONENT DIAGNOSIS >[ATX14B]
P1811 POWER SUPPLY CIRCUIT
FOR TRANSFER CONTROL UNIT
COMPONENT DIAGNOSIS
P1811 POWER SUPPLY CIRCUIT FOR TRANSFER CONTROL UNIT
DescriptionINFOID:0000000001737101
Power supply to transfer control unit is abnormally low while driving.
DTC LogicINFOID:0000000001737102
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:0000000001737103
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: March 2010 2008 QX56

P1810 NEUTRAL-4LO SWITCHDLN-29
< COMPONENT DIAGNOSIS > [ATX14B]
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B
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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: March 2010 2008 QX56

P1813 4WD SHIFT SWITCHDLN-31
< COMPONENT DIAGNOSIS > [ATX14B]
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B
DLN
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P1813 4WD SHIFT SWITCH
DescriptionINFOID:0000000001737118
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:0000000001737119
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:0000000001737120
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
ConditionVoltage (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: March 2010 2008 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 3.
• 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
ConnectorTerminal Voltage (Approx.)
M141 1 - Ground Battery voltage
PDIA0210E
Continuity should exist.SDIA2699E
Revision: March 2010 2008 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 TerminalConditionVoltage
(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: March 2010 2008 QX56

DLN-40
< COMPONENT DIAGNOSIS >[ATX14B]
P1817 ACTUATOR MOTOR

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 2.
2.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.
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.
SHIFT AC
MON2 • 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
Connector Terminal ConditionVoltage
(Approx.)
E142 4 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch: 4H to
4LO (Wait function is
operating.)
Battery
voltage
Except the above 0V
13 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch: 4LO
to 4H (Wait function is
operating.)
Battery
voltage
Except the above 0V
E143 33 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de- pressed 4WD shift switch: 4H to
4LO (Wait function is
operating.)
Battery
voltage
Except the above 0V
42 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N position
• Brake pedal de-
pressed 4WD shift switch: 4LO
to 4H (Wait function is
operating.)
Battery
voltage
Except the above 0V
Monitored
item Condition Display
value
SDIA2705E
Connector Terminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0310E
Revision: March 2010 2008 QX56

P1817 ACTUATOR MOTORDLN-41
< COMPONENT DIAGNOSIS > [ATX14B]
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G H
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M A
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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 3.
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 terminal 5and transfer shift low relay harness connector terminal 5.
3.CHECK ACTUATOR MOTOR GROUND 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 continuity between transfer shift high relay harness con- nector E46 terminals 2, 4 (A) and transfer shift low relay harness
connector E47 terminals 2, 4 (B) 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 TRANSFER SHIFT RELAY
1. Turn ignition switch OFF.
2. Remove transfer shift high relay and transfer shift low relay. Refer to DLN-16, "
Component Parts Loca-
tion".
3. Apply 12V direct current between transfer shift relay terminals 1
and 2.
4. Check continuity between relay terminals 3 and 4, 3 and 5.
Are the inspection results normal?
YES >> GO TO 5.
NO >> Replace the transfer shut off relay. Refer to DLN-16, "
Component Parts Location".
5.CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER SHIFT RELAY
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the transfer control device (actuator motor) har-
ness connector.
3. Remove transfer shift high relay and transfer shift low relay.
4. Check continuity between the following terminals.
Connector Terminal Voltage (Approx.)
A: E46 5 - Ground
Battery voltage
B: E47 5 - Ground
WDIA0311E
Continuity should exist.
WDIA0312E
Terminal ConditionContinuity
3 - 4 12V direct current supply between terminals 1 and 2 No
OFF
Yes
3 - 5 12V direct current supply between terminals 1 and 2 Yes
OFF
No
WIIA0291E
Revision: March 2010 2008 QX56

DLN-42
< COMPONENT DIAGNOSIS >[ATX14B]
P1817 ACTUATOR MOTOR
- Transfer control unit harness connector E143 terminal 33 and
transfer control device (actuator motor) harness connector F58
terminal 21.
- Transfer control unit harness connector E143 terminal 42 and transfer control device (actuator motor) harness connector F58
terminal 24.
- Transfer control unit harness connector E142 terminal 4 and transfer shift high relay harness connector E46 terminal 1 (A).
- Transfer control unit harness connector E142 terminal 13 and
transfer shift low relay harness connector E47 terminal 1 (B).
- Transfer control unit harness connector E143 terminal 33 and transfer shift high relay harness connector E46 terminal 3 (A).
- Transfer control unit harness connector E143 terminal 42 and
transfer shift low relay harness connector E47 terminal 3 (B).
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 ACTUATOR MOTOR
1. Remove transfer control device. Refer to DLN-134, "
Removal and Installation".
2. Check operation by applying battery voltage to transfer control device (actuator motor) terminals 21 and 24.
CAUTION:
• Do not operate actuator motor for more than 1 second.
• Change the actuator motor posi tion to HIGH when install-
ing.
• Be careful not to overheat the harness.
SDIA2710E
WDIA0314E
Continuity should exist.
WDIA0315E
Terminal Actuator motor
21 (Battery voltage) - 24 (Ground) Clockwise rotation
24 (Battery voltage) - 21 (Ground) Counterclockwise rotation
WDIA0224E
Revision: March 2010 2008 QX56

P1817 ACTUATOR MOTORDLN-43
< COMPONENT DIAGNOSIS > [ATX14B]
C
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G H
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M A
B
DLN
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3. Check resistance between transfer control device (actuator motor) terminals 21 and 24.
Are the inspection results normal?
YES >> GO TO 7.
NO >> Replace transfer control device (actuator motor).
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".
Component InspectionINFOID:0000000001737132
TRANSFER SHIFT RELAY
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. Apply 12V direct current between transfer shift relay terminals 1 and 2.
4. Check continuity between relay terminals 3 and 4, 3 and 5.
5. If NG, replace transfer shift relay.
TRANSFER CONTROL DEVICE
1. Remove transfer control device. Refer to DLN-134, "Removal and Installation".
2. Check operation by applying battery voltage to transfer control device (actuator motor) terminals 21 and 24.
CAUTION:
• Do not operate actuator moto r for more than 1 second.
• Change the actuator motor posi tion to HIGH when install-
ing.
• Be careful not to overheat the harness. 21 - 24 : Approx. 0.2
Ω
SDIA2726E
Terminal ConditionContinuity
3 - 4 12V direct current supply between terminals 1 and 2 No
OFF
Yes
3 - 5 12V direct current supply between terminals 1 and 2 Yes
OFF
No
WIIA0291E
TerminalActuator motor
21 (Battery voltage) - 24 (Ground) Clockwise rotate
24 (Battery voltage) - 21 (G round) Counterclockwise rotate
WDIA0224E
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