engine INFINITI QX56 2006 Factory Service Manual

TROUBLE DIAGNOSISTF-51
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Revision: November 2009 2006 QX56
Diagnostic Procedure
1. Warm up engine.
2. Move A/T selector lever to “P” position.
3. Turn 4WD shift switch to “2WD” position.
4. Turn ignition switch “ON” and “OFF ” at least twice, and then turn ignition switch “OFF”.
5. Turn 4WD shift switch to “AUTO” position.
6. Turn ignition switch “ON”. (Do not start engine.)
7. 4WD warning lamp ON. If 4WD warning lamp does not turn ON, refer to TF-121, "
4WD Warning Lamp Does Not Turn ON" .
8. Move A/T selector lever to “R” position.
9. Turn 4WD shift switch to “2WD”, “AUTO ” and “2WD ” in order.
10. Move A/T selector lever to “D” position.
11. Turn 4WD shift switch to “4H”, “AUTO ” and “4H” in order.
12. Move A/T selector lever to “N” position.
13. Turn 4WD shift switch to “AUTO” position.
14. Move A/T selector lever to “P” position.
15. Read the flickering of 4WD warning lamp. Refer to TF-51, "
Judgement Self-diagnosis" .
Judgement Self-diagnosis
When a malfunction is detected, the malfunction route is indicated by flickering of the 4WD warning lamp.
PDIA0227E
Flickering pattern or
flickering condition Items
Malfunction Check items
2 Output shaft revolution
signal (from TCM)

Malfunction is detected in output shaft revolution signal
that is output from TCM through CAN communication.

Improper signal is input while driving. TF-58, "
Output Shaft
Revolution Signal
(TCM)"
3
Clutch pressure sole-
noid signal
Proper voltage is not applied to clutch pressure solenoid
valve due to open or short circuit. TF-86, "Clutch Pres-
sure Solenoid"
4
2-4WD solenoid signal
Proper voltage is not applied to 2-4WD solenoid valve
due to open or short circuit. TF-91, "2-4WD Sole-
noid"
5
Transfer motor
Motor does not operate properly due to open or short cir-
cuit in transfer motor or motor relay. TF-95, "Transfer Motor"
6
Vehicle speed signal
(from ABS)

Malfunction is detected in vehicle speed signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication.

Improper signal is input while driving. TF-58, "
Vehicle Speed
Sensor (ABS)"
7
CAN communication
Malfunction has been detected from CAN communica-
tion line. TF-113, "CAN Commu-
nication Line"
8
AD converter
AD converter system of transfer control unit is malfunc-
tioning. TF-54, "Power Supply
Circuit For Transfer
Control Unit"

TF-52
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
9Transfer fluid tempera-
ture

Signal voltage from fluid temperature sensor is abnor-
mally high (Transfer fluid temperature is abnormally low)
while driving. TF-102, "Transfer Fluid
Temperature"
10
Neutral-4LO switch
Improper signal from neutral-4LO switch is input due to
open or short circuit. TF-59, "Neutral-4LO
Switch"
11
Clutch pressure switch

Improper signal from clutch pressure switch is input due
to open or short circuit.

Malfunction occurs in clutch pressure switch or hydraulic
circuit. TF-105, "
Clutch Pres-
sure Switch"
12
Line pressure switch

Improper signal from line pressure switch is input due to
open or short circuit.

Malfunction occurs in line pressure switch or hydraulic
circuit. TF-108, "
Line Pressure
Switch"
13
Engine speed signal
(from ECM)

Malfunction is detected in engine speed signal that is
output from ECM through CAN communication.

Improper signal is input while driving. TF-85, "
Engine Speed
Signal (ECM)"
14
Throttle position sen-
sor (from ECM)

Malfunction is detected in accelerator pedal position sig-
nal that is output from ECM through CAN communica-
tion.

Signal voltage from accelerator pedal position sensor is
abnormally high or low. TF-111, "
Throttle Posi-
tion Signal (ECM)"
15
Power supply
Power supply voltage for transfer control unit is abnor-
mally low while driving. TF-54, "Power Supply
Circuit For Transfer
Control Unit"
16
4WD shift switch
More than two switch inputs are simultaneously detected
due to short circuit of 4WD shift switch. TF-62, "4WD Shift
Switch"
17
ABS operation signal
(from ABS)

Malfunction is detected in ABS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-111, "ABS Operation
Signal (ABS)"
18
Wait detection switch
Improper signal from wait detection switch is input due to
open or short circuit. TF-66, "Wait Detection
Switch"
19
Actuator motor

Motor does not operate properly due to open or short cir-
cuit in actuator motor.

Malfunction is detected in the actuator motor. (When
4WD shift switch is operated and actuator motor is not
operated)

Malfunction is detected in transfer shift high relay and
transfer shift low relay. TF-70, "
Actuator
Motor", TF-54, "Power
Supply Circuit For
Transfer Control Unit"
20
Actuator position
switch

Improper signal from actuator position switch is input
due to open or short circuit.

Malfunction is detected in the actuator position switch. TF-77, "
Actuator Posi-
tion Switch"
21
Actuator circuit

Transfer control device actuator circuit is shorted or
open. (Malfunctions are detected when motor relay cir-
cuit is open/shorted or relay transfer shift circuit is open/
shorted.)

Malfunction occurs in transfer control device drive circuit. TF-81, "
Transfer Con-
trol Device"

Malfunction is detected in transfer shut off relay.
TF-54, "
Power Supply
Circuit For Transfer
Control Unit"
22
VDC operation signal
(from VDC)

Malfunction is detected in VDC operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-112, "VDC Opera-
tion Signal (ABS)"
23
TCS operation signal
(from TCS)

Malfunction is detected in TCS operation signal that is
output from ABS actuator and electric unit (control unit)
through CAN communication. TF-112, "TCS Opera-
tion Signal (ABS)"
Flickering pattern or
flickering condition Items
Malfunction Check items

TROUBLE DIAGNOSIS FOR SYSTEMTF-55
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Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
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.
OK or NG
OK >> GO TO 2.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.

Harness for short or open between battery and transfer control unit harness connector terminal
29.

Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1, and 3.

Harness for short or open between transfer shut off relay harness connector E69 terminal 2
and transfer control unit harness connector terminal 30.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5
and transfer control unit harness connector terminals 16 and 22.

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .

Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
ConnectorTerminal 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

TROUBLE DIAGNOSIS FOR SYSTEMTF-57
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Revision: November 2009 2006 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove transfer shut off relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer shut off relay termi- nals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
5. If NG, replace the transfer shut off relay. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Transfer Control UnitEDS002I5
DIAGNOSTIC PROCEDURE
1. INSPECTION START
Do you have CONSULT-II?
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. PERFORM SELF-DIAGNOSIS (WITH CONSULT-II)
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform the self-diagnosis again.
Is the
“CONTROL UNIT 1 [P1802]”, “CONTROL UNIT 2 [P1803]”, “CONTROL UNIT 3 [P1804]” or “CONTROL
UNIT 4 [P1809]” displayed?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
3. PERFORM SELF-DIAGNOSIS (WITHOUT CONSULT-II)
Without CONSULT-II
1. Perform the self-diagnosis and then erase self-diagnostic results. Refer to TF-50, "
SELF-DIAGNOSTIC
PROCEDURE (WITHOUT CONSULT-II)" and TF-53, "ERASE SELF-DIAGNOSIS" .
2. Perform the self-diagnosis again.
Do the self-diagnostic results indicate AD converter?
YES >> Replace transfer control unit. Refer to TF-132, "Removal and Installation" .
NO >> Inspection End.
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
SCIA1245E

TROUBLE DIAGNOSIS FOR SYSTEMTF-59
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Revision: November 2009 2006 QX56
Neutral-4LO SwitchEDS002I8
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.Monitored item
Content ConditionDisplay value
N POSI SW TF [ON/
OFF] Condition of neutral-4LO
switch

Vehicle stopped

Engine running

A/T selector lever “
N”
position

Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.) OFF
→ ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON →
OFF
4WD shift switch: 4LO ON
TerminalWire
color Item
ConditionData (Approx.)
25 V Neutral-4LO switch

Vehicle stopped

Engine running

A/T selector
lever “N ” position

Brake pedal
depressed 4WD shift switch: 2WD, AUTO or 4H Battery voltage
4WD shift switch: 4H to 4LO (While actua-
tor motor is operating.)
Battery volt-
age
→ 0V
4WD shift switch: 4LO to 4H (While actua-
tor motor is operating.) 0V
→ Battery
voltage
4WD shift switch: 4LO 0V

TF-60
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK 4LO POSITION SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out the value of “N POSI SW TF”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND NEUTRAL-4LO SWITCH
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector 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.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value

Vehicle stopped

Engine running

A/T selector lever “N ” position

Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.) OFF →
ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→ OFF
4WD shift switch: 4LO ON
SDIA2692E
ConnectorTerminal
(Wire
color) Condition
Voltage
(Approx.)
E143 25 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N ” position

Brake pedal
depressed 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
SDIA2693E
Continuity should exist.
SDIA2694E

TF-62
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF ”. (Stay for at least 5 seconds.)
2. Disconnect neutral-4LO switch harness connector.
3. Remove neutral-4LO switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release neutral-4LO switch and check continuity between neutral-4LO switch terminals 12 and 13.
5. If NG, replace the neutral-4LO switch. Refer to TF-22, "
Location
of Electrical Parts" .
4WD Shift SwitchEDS002I9
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.Terminal
Condition Continuity
12 - 13 Push neutral-4LO switch
Yes
Release neutral-4LO switch No
SDIA2696E
Monitored item [Unit]Content ConditionDisplay value
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
4WD MODE [AUTO/
LOCK/2WD/4L] Control status of 4WD
(Output condition of 4WD
shift indicator lamp and
4LO indicator lamp)

Vehicle stopped

Engine running

A/T selector lever
“N ”
position

Brake pedal depressed 4WD shift switch: 2WD
2WD
4WD shift switch: AUTO AUTO
4WD shift switch: 4H LOCK
4WD shift switch: 4LO 4L
Te r m i n a lWire
color Item
ConditionData (Approx.)
9G/W 4WD shift switch
(2WD) Ignition switch: ON4WD shift switch: 2WD
Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
18 O 4WD shift switch
(4H) Ignition switch: ON4WD shift switch: 4H
Battery voltage
4WD shift switch: 2WD, AUTO or 4LO 0V
23 R 4WD shift switch
(4LO) Ignition switch: ON4WD shift switch: 4LO
Battery voltage
4WD shift switch: 2WD, AUTO or 4H 0V
24 LG/R 4WD shift switch
(AUTO) Ignition switch: ON4WD shift switch: AUTO
Battery voltage
4WD shift switch: 2WD, 4H or 4LO 0V

TROUBLE DIAGNOSIS FOR SYSTEMTF-63
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Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK 4WD SHIFT SWITCH SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out ON/OFF switching action of the “2WD SWITCH”,
“AUTO SWITCH”, “LOCK SWITCH”, “4L SWITCH ” with operat-
ing 4WD shift switch.
Without CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
SDIA2697E
Connector Terminal ConditionVoltage
(Approx.)
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

TF-64
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
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.
OK or NG
OK >> GO TO 3.
NG >> Go to TF-54, "
Power Supply Circuit For Transfer Control
Unit" .
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.
OK or NG
OK >> GO TO 4.
NG >> 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 PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .
Connector Terminal Voltage (Approx.)
M141 1 - Ground 0V
SDIA2383E
ConnectorTerminal Voltage (Approx.)
M141 1 - Ground Battery voltage
PDIA0210E
Continuity should exist.SDIA2699E

TF-66
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
COMPONENT INSPECTION
1. Turn ignition switch “OFF ”. (Stay for at least 5 second.)
2. Disconnect 4WD shift switch harness connector.
3. Operate 4WD shift switch and check continuity between 4WD shift switch terminals.
4. If NG, replace the 4WD shift switch.
Wait Detection SwitchEDS002IA
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals. Connector Terminal
ConditionContinuity
M141 1 - 2
4WD shift switch: 2WD
Yes
4WD shift switch: AUTO, 4H and
4LO No
1 - 3 4WD shift switch: AUTO
Yes
4WD shift switch: 2WD, 4H and
4LO No
1 - 4 4WD shift switch: 2WD
No
4WD shift switch: AUTO, 4H and
4LO Ye s
1 - 5 4WD shift switch: 4H
Yes
4WD shift switch: 2WD, AUTO,
and 4LO No
1 - 6 4WD shift switch: 4LO
Yes
4WD shift switch: 2WD, AUTO
and 4H No
WDIA0205E
Monitored item
Content ConditionDisplay value
WAIT DETCT SW [ON/
OFF] Condition of wait detection
switch

Vehicle stopped

Engine running

A/T selector lever
“N ”
position

Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator
motor is operating.) OFF
→ ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON →
OFF
4WD shift switch: 4LO ON
Te r m i n a lWire
color Item
ConditionData (Approx.)
43 G/Y Wait detection switch

Vehicle stopped

Engine running

A/T selector
lever “N ” position

Brake pedal
depressed 4WD shift switch: 2WD, AUTO or 4H Battery voltage
4WD shift switch: 4H to 4LO (While actua-
tor motor is operating.)
Battery volt-
age
→ 0V
4WD shift switch: 4LO to 4H (While actua-
tor motor is operating.) 0V
→ Battery
voltage
4WD shift switch: 4LO 0V