4WD INFINITI QX56 2006 Factory Service Manual

TROUBLE DIAGNOSIS FOR SYSTEMTF-103
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Revision: November 2009 2006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER FLUID TEMPERATURE SENSOR 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 “FLUID TEMP SE”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector terminals and ground.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND TRANSFER TERMINAL CORD
ASSEMBLY 1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and transfer terminal cord assembly harness connec- tor.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E143 terminal 28 and
transfer terminal cord assembly harness connector F56 terminal
3.
–Transfer control unit harness connector E143 terminal 31 and
transfer terminal cord assembly harness connector F56 terminal
2.
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
(Approx.)
Transfer fluid temperature approx. 20 - 80 °C (68 - 176°F) 1.1 - 0.3V
SDIA2741E
Connector Terminal ConditionData
(Approx.)
E143 28 -
Ground Always
0V
31 -
Ground Ignition switch:
ON Transfer fluid temperature
approx. 20
°C (68°F) 1.1V
Transfer fluid temperature
approx. 80 °C (176°F) 0.3V
SDIA2742E
Continuity should exist.
SDIA2743E

TROUBLE DIAGNOSIS FOR SYSTEMTF-105
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Revision: November 2009 2006 QX56
Clutch Pressure SwitchEDS002IK
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 [Unit]
Content ConditionDisplay value
CL PRES SW [ON /
OFF] Condition of clutch pres-
sure switch

Vehicle stopped

Engine running

A/T selector lever “
D” position

4WD shift switch: AUTO or 4H ( “Wait ” function is not
operating.) ON

Vehicle stopped

Engine running

4WD shift switch: 2WD (
“Wait ” function is not oper-
ating.) OFF
Terminal
Wire
color Item
ConditionData (Approx.)
34 BR Clutch pressure switch

Vehicle stopped

Engine running

A/T selector
lever “D ” position 4WD shift switch: AUTO or 4H (
“Wait ”
function is not operating.) 0V

Vehicle stopped

Engine running4WD shift switch: 2WD (
“Wait ” function is
not operating.) Battery voltage

TF-106
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK CLUTCH PRESSURE SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out ON/OFF switching action of the “CL PRES SW ” while
operating 4WD shift switch.
Without CONSULT-II
1. 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.
2. CHECK HARNESS BETWEEN TRANSFER 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.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value

Ignition switch: ON

A/T selector lever “D ”
position 4WD shift switch: AUTO or 4H
(
“ Wait ” function is not operating.) ON
Ignition switch: ON 4WD shift switch: 2WD (
“Wait ”
function is not operating.) OFF
Connector Terminal ConditionVoltage
(Approx.)
E143 34 -
Ground

Ignition switch: ON

A/T selector lever
“ D ” position 4WD shift switch:
AUTO or 4H
(
“ Wait ” function is
not operating.) 0V
Ignition switch: ON 4WD shift switch:
2WD (
“Wait ” func-
tion is not operat-
ing.) Battery
voltage
WDIA0141E
SDIA2746E
Continuity should exist.
SDIA2747E

TF-108
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
Line Pressure SwitchEDS002IL
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 [Unit]
Content ConditionDisplay value
LINE PRES SW [ON/
OFF] Condition of line pressure
switch

A/T selector lever
“D ” position

4WD shift switch: 2WD, AUTO or 4H ON

Except the above

The vehicle has been
left at room tempera-
ture for 5 minutes and
more with ignition
switch in
“OFF ” posi-
tion.
Ignition switch: ON

A/T selector lever: "P"
or "N" position

4WD shift switch: other
than AUTO OFF
Terminal
Wire
color Item
ConditionData (Approx.)
35 BR/W Line pressure switch

Ignition switch: ON

A/T selector lever “D ” posi-
tion
4WD shift switch: AUTO 0V

Except the above

The vehicle has been left at
room temperature for 5 min-
utes and more with ignition
switch in “OFF ” position.

Ignition switch: ON

A/T selector lever: "P" or "N"
position

4WD shift switch: other than
AUTO Battery voltage

TROUBLE DIAGNOSIS FOR SYSTEMTF-109
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DIAGNOSTIC PROCEDURE
1. CHECK LINE PRESSURE SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR ” mode for “ALL MODE AWD/4WD ” with CONSULT-II.
3. Read out ON/OFF switching action of “LINE PRES SW ” while
operating 4WD shift switch.
Without CONSULT-II
1. 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.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL 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.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
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
ignition switch in “
OFF”
position.
Ignition switch: ON

A/T selector lever: "P" or "N"
position

4WD shift switch: other than
AUTO OFF
Connector Terminal Condition Voltage
(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
lever: "P" or "N"
position

4WD shift
switch: other
than AUTO Battery
voltage
WDIA0142E
SDIA2751E
Continuity should exist.
SDIA2752E

TROUBLE DIAGNOSIS FOR SYSTEMTF-113
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Revision: November 2009 2006 QX56
CAN Communication LineEDS002IQ
DIAGNOSTIC PROCEDURE
1. CHECK CAN COMMUNICATION CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON” and start engine.
2. Select “SELF-DIAG RESULTS ” mode for “ALL MODE AWD/4WD ” within CONSULT-II.
3. Perform the self-diagnosis.
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Print CONSULT-II screen and go to LAN-3, "Precautions
When Using CONSULT-II" .
NO >> Inspection End.
ATP SwitchEDS002IR
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.
SDIA1850E
Monitored item [Unit] Content ConditionDisplay value
ATP SWITCH [ON/OFF] Condition of ATP switch

Vehicle stopped

Engine running

A/T selector lever “ N"

Brake pedal depressed 4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is
operating.)
ON
Except the above OFF
TerminalWire
color Item
ConditionData (Approx.)
40 L ATP switch

Vehicle stopped

Engine running

A/T selector
lever “N"

Brake pedal
depressed 4WD shift switch: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)
0V
Except the above Battery voltage

TF-114
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
DIAGNOSTIC PROCEDURE
1. CHECK ATP 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 “AT P S W I T C H”.
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 ATP SWITCH
1. Turn ignition switch “ OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the ATP switch harness connector.
3. Check continuity between transfer control unit harness connec- tor E143 terminal 40 and ATP switch harness connector F55 ter-
minal 8.
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"

Brake pedal
depressed 4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)
ON
Except the above OFF
SDIA2391E
Connector TerminalConditionVoltage
(Approx.)
E143 40 -
Ground

Vehicle stopped

Engine running

A/T selector lever
“ N"

Brake pedal
depressed 4WD shift switch: 4H
to 4LO or 4LO to 4H
(While actuator motor
is operating.)
0V
Except the above Battery
voltage
SDIA2755E
Continuity should exist.
SDIA2756E

TROUBLE DIAGNOSIS FOR SYSTEMTF-115
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Revision: November 2009 2006 QX56
3. CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Check continuity between ATP switch harness connector F55 terminal 9 and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release ATP switch and check continuity between ATP switch terminals 8 and 9.
OK or NG
OK >> GO TO 5.
NG >> Replace ATP switch. Refer to TF-22, "
Location of Elec-
trical Parts" .
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-35, "
Transfer Control Unit Input/Output Signal Ref-
erence Values" .
OK or NG
OK >> GO TO 6.
NG >> Check transfer control unit pin terminals for damage or loose connection with harness connector. If any items are damaged, repair or replace damaged parts.
6. CHECK ATP WARNING LAMP
1. Turn ignition switch “ON”. (Do not start engine.)
2. Move A/T selector lever to "P" position.
3. Set 4WD shift switch from "4H" to "4LO" or "4LO" to "4H".
Does ATP warning lamp turn ON while switching?
YES >> GO TO TF-125, "ATP Warning Lamp Turns ON" .
NO >> Inspection End.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 second.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts" .
Continuity should exist.
SDIA2394E
Terminal
Condition Continuity
8 - 9 Push ATP switch
Yes
Release ATP switch No
SDIA2757E

TROUBLE DIAGNOSIS FOR SYMPTOMSTF-117
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Revision: November 2009 2006 QX56
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ONEDS002HM
SYMPTOM:
4WD shift indicator lamp and 4LO indicator lamp do not turn ON for approx. 1 second when turning
ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
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 SYMPTOMSTF-121
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Revision: November 2009 2006 QX56
4WD Warning Lamp Does Not Turn ONEDS002HN
SYMPTOM:
4WD warning lamp does not turn ON when turning ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
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 4.
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