2005 INFINITI QX4 air condition

TROUBLE DIAGNOSIS FOR SYSTEM
TF-103
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Revision: October 20052005 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 (B/G)
and transfer terminal cord assembly harness connector F56 ter-
minal 3 (B/G).
–Transfer control unit harness connector E143 terminal 31 (G)
and transfer terminal cord assembly harness connector F56 ter-
minal 2 (G).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
ConditionDisplay value
(Approx.)
Transfer fluid temperature approx. 20 - 80°C (68 - 176°F) 1.1 - 0.3V
SDIA2741E
ConnectorTe r m i n a l
(Wire
color)ConditionData
(Approx.)
E14328 (B/G)
- GroundAlways 0V
31 (G) -
GroundIgnition switch:
ONTransfer fluid temperature
approx. 20°C (68°F)1.1V
Transfer fluid temperature
approx. 80°C (176°F)0.3V
SDIA2742E
Continuity should exist.
SDIA2743E

TF-106
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 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 (BR) and transfer terminal cord assembly
harness connector F56 terminal 7 (BR)
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”
position4WD shift switch: AUTO or 4H
(“Wait” function is not operating.)ON
Ignition switch: ON4WD shift switch: 2WD (“Wait”
function is not operating.)OFF
ConnectorTerminal
(Wire
color)ConditionVoltage
(Approx.)
E14334 (BR) -
Ground

Ignition switch: ON

A/T selector lever
“D” position4WD shift switch:
AUTO or 4H
(“Wait” function is
not operating.)0V
Ignition switch: ON4WD shift switch:
2WD (“Wait” func-
tion is not operat-
ing.)Battery
voltage
WDIA0141E
SDIA2746E
Continuity should exist.
SDIA2747E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-107
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Revision: October 20052005 QX56
3. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-54, "
TRANSFER CONTROL UNIT TERMINALS
AND REFERENCE VALUE" .
OK or NG
OK >> GO TO 4.
NG >> Check transfer control unit pin terminals for damage or loose connection with the harness connec-
tor. If any items are damaged, repair or replace damaged parts.
4. CHECK CLUTCH PRESSURE SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to TF-22, "
Location of Electrical Parts" .
3. Push and release clutch pressure switch and check continuity
between transfer terminal cord assembly terminal 7 and ground.
OK or NG
OK >> GO TO 5.
NG >> Replace clutch pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
5. CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> GO TO 6.
NG >> Replace transfer control unit. Refer to TF-132, "
Removal and Installation" .
6. CRUISE TEST
Perform cruise test. Refer to TF-34, "
CRUISE TEST" .
OK or NG
OK >> Inspection End.
NG >> Perform the applicable trouble diagnosis.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove clutch pressure switch. Refer to TF-22, "
Location of Electrical Parts" .
3. Push and release clutch pressure switch and check continuity
between transfer terminal cord assembly terminal 7 and ground.
4. If NG, replace the clutch pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Terminal Condition Continuity
7 -
GroundPush clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E
Terminal Condition Continuity
7 - GroundPush clutch pressure switch Yes
Release clutch pressure switch No
WDIA0171E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-109
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Revision: October 20052005 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 (BR/W) and transfer terminal cord assem-
bly harness connector F56 terminal 1 (BR/W).
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: AUTOON

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
AUTOOFF
ConnectorTe r m i n a l
(Wire
color)ConditionVoltage
(Approx.)
E14335 (BR/
W) -
Ground

A/T selector lever
“D” position4WD shift switch:
AUTO0V

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 AUTOBattery
voltage
WDIA0142E
SDIA2751E
Continuity should exist.
SDIA2752E

TF-110
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 QX56
3. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-36, "
Transfer Control Unit Input/Output Signal Ref-
erence Values" .
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

Transfer control unit pin terminals for damage or loose connection with harness connector.

Transfer control unit. Refer to TF-132, "Removal and Installation" .
4. CHECK LINE PRESSURE SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to TF-22, "
Location of Electrical Parts" .
3. Push and release line pressure switch and check continuity
between transfer terminal cord assembly terminal 1 and ground.
OK or NG
OK >> GO TO 5.
NG >> Replace line pressure switch. Refer to TF-22, "
Location
of Electrical Parts" .
5. CHECK DTC
Perform the self-diagnosis, after driving a vehicle for a while.
OK or NG
OK >> GO TO 6.
NG >> Replace transfer control unit. Refer to TF-132, "
Removal and Installation" .
6. CRUISE TEST
Perform cruise test. Refer to TF-34, "
CRUISE TEST" .
OK or NG
OK >> INSPECTION END.
NG >> Perform the applicable trouble diagnosis.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Remove line pressure switch. Refer to TF-22, "
Location of Electrical Parts" .
3. Push and release line pressure switch and check continuity
between transfer terminal cord assembly terminal 1 and ground.
4. If NG, replace the line pressure switch. Refer to TF-22, "
Loca-
tion of Electrical Parts" .
Terminal Condition Continuity
1 -
GroundPush line pressure switch Yes
Release line pressure switch No
WDIA0172E
Terminal Condition Continuity
1 - GroundPush line pressure switch Yes
Release line pressure switch No
WDIA0172E

TF-114
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 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 “ATP SWITCH”.
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 (L) and ATP switch harness connector F55
terminal 8 (L/Y).
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
depressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.) ON
Except the above OFF
SDIA2391E
ConnectorTe r m i n a l
(Wire
color)ConditionVoltage
(Approx.)
E14340 (L) -
Ground

Vehicle stopped

Engine running

A/T selector lever
“N"

Brake pedal
depressed4WD shift switch: 4H
to 4LO or 4LO to 4H
(While actuator motor
is operating.)0V
Except the aboveBattery
voltageSDIA2755E
Continuity should exist.
SDIA2756E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-115
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Revision: October 20052005 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 (B) 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-36, "
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 - 9Push ATP switch Yes
Release ATP switch No
SDIA2757E

TF-128
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
5. CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to TF-36, "
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 TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to TF-144, "
Disassembly and Assembly" .
2. Check transfer inner parts.
OK or NG
OK >> Inspection End.
NG >> Repair or replace damaged parts.
4WD Warning Lamp Flashes RapidlyEDS002HR
SYMPTOM:
While driving, 4WD warning lamp flashes rapidly.
NOTE:
Rapid flashing: 2 times/second
DIAGNOSTIC PROCEDURE
1. CHECK TIRE
Check the following.

Tire pressure

Wear condition

Longitudinal tire size (There is no difference between longitudinal tires.)
OK or NG
OK >> GO TO 2.
NG >> Repair or replace damaged parts.
2. CHECK 4WD WARNING LAMP
Stop the vehicle and allow it to idle for a short period of time.
Does flashing stop?
YES >> Inspection End.
NO >> GO TO 3.
3. CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fluid temperature system. Refer to TF-102, "
Transfer Fluid Temperature"
.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 5.