2006 INFINITI QX56 engine

TF-98
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: November 20092006 QX56
2. Check voltage between transfer control unit harness connector
terminal and ground.
OK or NG
OK >> GO TO 7.
NG >> GO TO 2.
Connector Terminal ConditionVoltage (Approx.)
E142 14 -
Ground

Accelera-
tor pedal
depressed

Ve h ic le
stopped

Engine
running

Brake
pedal
depressed 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
(Except 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
selector lever “P ”
position) 0V
E143 41 -
Ground

Accelera-
tor pedal
depressed

Ve h ic le
stopped

Engine
running

Brake
pedal
depressed 4WD shift switch:
2WD
0V
4WD shift switch:
AUTO or 4LO (A/T
selector lever “P ” or
“ N ” position) 0V
(Battery voltage
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) Battery voltage
4WD shift switch:
4H (A/T selector
lever “P ” position) 0V
(Battery voltage
for approx. 2 sec.
after shifting to
“
P ”.)
4WD shift switch:
4H (Except for A/T
selector lever “P ”
position) Battery voltage
SDIA2735E

TROUBLE DIAGNOSIS FOR SYSTEMTF-99
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TF
Revision: November 2009 2006 QX56
2. CHECK TRANSFER MOTOR RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Disconnect transfer motor relay.
4. Check voltage between transfer motor relay harness connector terminals and ground.
5. Turn ignition switch “ON”. (Do not start engine.)
6. Check voltage between transfer motor relay harness connector terminals and ground.
OK or NG
OK >> GO TO 3.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

20A fuse No. 58 located in the fuse and relay box. Refer to PG-4, "POWER SUPPLY ROUTING
CIRCUIT" .

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

Harness for short or open between battery and transfer motor relay harness connector E154
terminal 5.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5
and transfer motor relay harness connector E153 terminal 2.

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .
3. CHECK TRANSFER MOTOR RELAY
1. Turn ignition switch “OFF”.
2. Remove transfer motor relay. Refer to TF-22, "
Location of Electrical Parts" .
3. Apply 12V direct current between transfer motor relay terminals 1 and 2.
4. Check continuity between relay terminals 3 and 5.
OK or NG
OK >> GO TO 4.
NG >> Replace the transfer motor relay.
Connector Terminal Voltage (Approx.)
E153 2 - Ground 0V
E154 5 - Ground Battery voltage
WDIA0169E
ConnectorTerminal Voltage (Approx.)
E153 2 - Ground
Battery voltage
E154 5 - Ground
WDIA0170E
Condition Continuity
12V direct current supply between terminals 1 and 2 Yes
OFF No
LDIA0098E

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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

TROUBLE DIAGNOSIS FOR SYSTEMTF-109
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Revision: November 2009 2006 QX56
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

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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