clutch INFINITI QX56 2004 Factory Service Manual

ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
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Revision: August 20072004 QX56
3. Display changes to “NOW ADJUSTING” in a short time.
4. When clutch force release limit value is set to “1.2 kgm”, current
value “0.3 kgm” shown on display will be replaced by “1.2 kgm”
and “ADJUSTMENT COMPLETE” will appear at the same time.
Clutch force release limit value setting is now complete.
SMT969D
SMT970D

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-57
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Revision: August 20072004 QX56
30Power supply for A/D
converter &Ignition key is set to ON position. 4.5 - 5.5V
Ignition key is set to OFF position. 0V
31Transfer fluid tempera-
ture sensor &At 20°C (68°F) 1.1V
At 80°C (176°F) 0.3V
33 Transfer shift relay (High)
&While actuator is operating from “4H”
to “4LO”Battery voltage
Actuator does not operate. 0V
34 Clutch pressure switch4WD shift switch is set to AUTO or
4H, then A/T selector lever is set to D
position. (wait detection system:
OFF)Battery voltage
4WD shift switch is set to 2WD,
AUTO or 4H, then A/T selector lever
is set to D position. (wait detection
system: ON)0V
35 Line pressure switch4WD shift switch is set to 2WD,
AUTO or 4H, then A/T selector lever
is set to D position.Battery voltage
—0V
36 CONSULT-II (RX) — — —
40 ATP switch
&A/T selector lever is set to P position. Battery voltage
A/T selector lever is set to any posi-
tion other than P.Less than 1V
41Transfer motor relay
monitorTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
42Transfer shift relay
(LOW)While actuator is operating from
“4LO” to “4H” positionBattery voltage
Actuator does not operate. 0V
43 Wait detection switch4WD shift switch is set to any posi-
tion other than 4LO.Battery voltage
4WD shift switch is set to 4LO posi-
tion.*3Less than 1V
44Transfer 4LO actuator
switch4WD shift switch is set to any posi-
tion other than 4LO. (Actuator: High
position)Battery voltage
4WD shift switch is set to 4LO posi-
tion. (Actuator: Low position)Less than 1V
45 Ground — — — Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)

TF-60
4WD SOLENOID VALVE
Revision: August 20072004 QX56
4WD SOLENOID VALVEPFP:00000
Diagnostic ProcedureEDS00183
1. CHECK 4WD SOLENOID VALVE
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH PRESSURE
SWITCH AND LINE PRESSURE SWITCH" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace 4WD solenoid valve.
2. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connector E142.
3. Check resistance between transfer terminal cord assembly har-
ness connector F56 terminal 6 (L) and transfer control unit har-
ness connector E142 terminal 10 (L/W).
OK or NG
OK >> GO TO 3.
NG >> Check the following.

Transfer dropping resistor
Refer to TF-96, "
TRANSFER DROPPING RESISTOR" .

Continuity between transfer terminal cord assembly harness connector F56 terminal 6 (L) and
transfer dropping resistor harness connector E135 terminal 2 (L).

Continuity between transfer dropping resistor harness connector E135 terminal 1 (L/W) and
transfer control unit harness connector E142 terminal 10 (L/W).
3. CHECK POWER SOURCE CIRCUIT
1. Turn ignition switch to OFF position.
2. Check continuity between transfer terminal cord assembly har-
ness connector F56 terminal 6 (L) and transfer control unit har-
ness connector E142 terminal 19 (L).
Continuity should exist.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace harness between transfer terminal
cord assembly harness connector F56 terminal 6 (L)
and transfer control unit harness connector E142 termi-
nal 19 (L).
SMT775D
Resistance : 11.2 - 12.8Ω
LDIA0067E
LDIA0068E

TF-72
CLUTCH PRESSURE SWITCH
Revision: August 20072004 QX56
CLUTCH PRESSURE SWITCHPFP:00000
Diagnostic ProcedureEDS00188
1. CHECK MALFUNCTION
Is this malfunction detected only while driving in reverse?
Ye s o r N o
Yes >> Check A/T PNP switch "R" position.

Refer to AT-109, "DTC P0705 PARK/NEUTRAL POSITION SWITCH" .
No >> GO TO 2.
2. CHECK OTHER MALFUNCTION
Are other malfunctions also detected by self-diagnosis and CONSULT-II?
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and TF-31, "Trouble Diagnosis with CONSULT-II" .
Ye s o r N o
Yes >> Check for other malfunctions.

(When other malfunctions are eliminated, clutch pressure switch malfunction display may dis-
appear.)
No >> GO TO 3.
3. CHECK 2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH CIRCUITS
Check 2-4WD shift solenoid valve and 4WD shift switch circuits.
OK or NG
OK >> GO TO 4.
NG >> Check, repair or replace faulty parts.
4. CHECK INPUT SIGNAL
Do you have CONSULT-II?
Ye s o r N o ?
Yes >> GO TO 5.
No >> GO TO 6.

CLUTCH PRESSURE SWITCH
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Revision: August 20072004 QX56
5. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch to ON position.
2. Select “ECU INPUT SIGNALS” in Data Monitor.
3. Put A/T selecor lever in D.
4. Turn 4WD shift switch to 4H and back to 2WD while reading out
ON/OFF status of "CL PRES SW".
OK or NG
OK >> GO TO 7.
NG >> Check the following.

Continuity between transfer control unit and transfer
terminal cord assembly harness connector

Clutch pressure switch.
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH
PRESSURE SWITCH AND LINE PRESSURE
SWITCH" .
6. CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ON position and set 4WD shift switch to
4H position.
2. Check voltage between transfer control unit harness connector
E143 terminal 34 (BR) and ground. Refer to TF-55, "
Transfer
Control Unit Terminals and Reference Value"
OK or NG
OK >> GO TO 7.
NG >> Check the following.

Continuity between transfer control unit and transfer
terminal cord assembly harness connector

Clutch pressure switch.
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH PRESSURE SWITCH AND LINE PRES-
SURE SWITCH" .
7. PERFORM SELF-DIAGNOSIS AGAIN
1. Check hydraulic parts.
2. After driving for a while, perform self-diagnosis again. Refer to TF-27, "
Trouble Diagnosis without CON-
SULT-II" .
OK or NG
OK >> Inspection End.
NG >> 1. Perform transfer control unit input/output signal inspection. Refer to TF-55, "
TRANSFER CON-
TROL UNIT INSPECTION TABLE" .
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with harness
connector.
SMT788D
WDIA0087E
LDIA0075E

TF-74
LINE PRESSURE SWITCH
Revision: August 20072004 QX56
LINE PRESSURE SWITCHPFP:00000
Diagnostic ProcedureEDS00189
1. CHECK MALFUNCTION
Is this malfunction detected only while driving in reverse?
Ye s o r N o
Yes >> Check A/T PNP switch “R” position.

Refer to AT-109, "DTC P0705 PARK/NEUTRAL POSITION SWITCH" .
No >> GO TO 2.
2. CHECK OTHER MALFUNCTIONS
Are other malfunctions also detected by self-diagnosis and CONSULT-II?
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and TF-31, "Trouble Diagnosis with CONSULT-II" .
Ye s o r N o
Yes >> Check for other malfunctions.

(When other malfunctions are eliminated, line pressure switch malfunction display may disap-
pear.)
No >> GO TO 3.
3. CHECK INPUT SIGNAL
Do you have CONSULT-II?
Ye s o r N O
Yes >> GO TO 4.
No >> GO TO 5.
4. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “ECU INPUT SIGNALS” in Data Monitor.
2. Put A/T selector lever in D.
3. Turn the 4WD shift switch to 4H and back to 2WD while reading
out ON/OFF status of "LINE PRES SW".
OK or NG
OK >> GO TO 6.
NG >> Check the following.

Continuity between transfer control unit and transfer
terminal cord assembly harness connector

Line pressure switch
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH
PRESSURE SWITCH AND LINE PRESSURE
SWITCH" .
SMT790D
WDIA0087E

LINE PRESSURE SWITCH
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Revision: August 20072004 QX56
5. CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ON position.
2. Check voltage between transfer control unit harness connector E143 terminal 35 (BR/W) and ground.
OK or NG
OK >> GO TO 6.
NG >> Check the following.

Continuity between transfer control unit and transfer terminal cord assembly harness connector

Line pressure switch
Refer to TF-95, "
4WD SOLENOID VALVE, CLUTCH PRESSURE SWITCH AND LINE PRES-
SURE SWITCH" .
6. PERFORM SELF-DIAGNOSIS AGAIN
1. Check hydraulic parts.
2. After driving for a while, perform self-diagnosis again. Refer to TF-27, "
Trouble Diagnosis without CON-
SULT-II" .
OK or NG
OK >> Inspection End.
NG >> 1. Perform transfer control unit input/output signal inspection. Refer to TF-55, "
TRANSFER CON-
TROL UNIT INSPECTION TABLE" .
2. If NG, recheck transfer control unit pin terminals for damage or loose connection with harness
connector. After the vehicle has
been left for at least 5
minutes at room tem-
perature with ignition
switch OFF: Approx. 0 volts should
exist.
With ignition switch in
ON, 4WD shift switch in
AUTO or 4H and A/T
selector lever in D: Battery voltage should
exist.
LDIA0076E
LDIA0077E

TROUBLE DIAGNOSES FOR SYMPTOMS
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Revision: August 20072004 QX56
Symptom 8. Tight Corner Braking Symptom (Tight Corner Braking Symptom
Occurs-Hydraulic System Failure)
EDS0018L
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “ECU INPUT SIGNALS” in Data Monitor.
2. Put A/T selector lever in D.
3. Turn 4WD shift switch to 4H and back to 2WD while reading out
ON/OFF status of "CL PRES SW".
Without CONSULT-II
Check voltage between transfer control unit harness connector E143
terminal 34 (BR) and ground.
Refer to TF-55, "
TRANSFER CONTROL UNIT INSPECTION
TABLE" .
OK or NG
OK >> Disassemble transfer unit and check the following.

Control valve assembly

4WD solenoid valve

2-4WD shift solenoid valve

Clutch piston

Clutch assembly
NG >> GO TO 2.
2. CHECK CLUTCH PRESSURE SWITCH CIRCUIT
Check clutch pressure switch circuit.
Refer to TF-72, "
Diagnostic Procedure" .
OK or NG
OK >> GO TO 3.
NG >> Check, repair or replace faulty parts.
3. CHECK PROCEDURES FROM THE BEGINNING AGAIN
Check again.
OK or NG
OK >> Inspection End.
NG >> Recheck each connector pin terminals for damage or loose connection.
WDIA0087E

TF-94
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
Symptom 9. 4WD System Does Not Operate (The Vehicle Cannot Be Put Into
4WD Mode-Hydraulic System Failure)
EDS0018M
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “ECU INPUT SIGNALS” in Data Monitor.
2. Put A/T selector lever in D.
3. Turn 4WD shift switch to 4H and back to 2WD while reading out
ON/OFF status of "CL PRES SW".
Without CONSULT-II
Check voltage between transfer control unit harness connector E143
terminal 34 (BR) and ground.
Refer to TF-55, "
TRANSFER CONTROL UNIT INSPECTION
TABLE" .
OK or NG
OK >> 1. Check transfer fluid level.
2. Disassemble transfer unit and check the following.
–Transfer motor
–Main oil pump assembly
–Sub-oil pump assembly
–Oil strainer
–Control valve assembly
–2-4WD shift solenoid valve
–Oil filter element
–Lip seal
–Strainer O-ring
–Main oil pump drive gear
–Seal ring
–D-ring
–Clutch piston
–Clutch assembly
NG >> GO TO 2.
2. CHECK CLUTCH PRESSURE CIRCUIT
Check clutch pressure switch circuit.
Refer to TF-72, "
Diagnostic Procedure" .
OK or NG
OK >> GO TO 3.
NG >> Check, repair or replace faulty parts.
3. CHECK PROCEDURES FROM THE BEGINNING
Check again.
OK or NG
OK >> Inspection End.
NG >> Recheck each connector pin terminals for damage or loose connection.
WDIA0087E

TROUBLE DIAGNOSES FOR SYMPTOMS
TF-95
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Revision: August 20072004 QX56
Component InspectionEDS0018N
4WD SHIFT SWITCH
Check continuity between each terminal.
2-4WD SHIFT SOLENOID VALVE AND TRANSFER FLUID TEMPERATURE SENSOR
Measure resistance between terminals of transfer terminal cord
assembly harness connector F56.
4WD SOLENOID VALVE, CLUTCH PRESSURE SWITCH AND LINE PRESSURE SWITCH
Measure resistance between terminals of transfer terminal cord
assembly harness connector F56.
Terminals Switch position Continuity
1 - 22WD Yes
Except 2WD No
1 - 3, 1 - 4AUTO Yes
Except AUTO No
1 - 4, 1 - 54H Yes
Except 4H No
1 - 4, 1 - 64LO Yes
Except 4LO No
WDIA0090E
Component parts TerminalsResistance
(Approx.)
2-4WD shift solenoid valve 4 - 520°C (68°F):
22.8 - 25.2Ω
Transfer fluid temperature
sensor2 - 320°C (68°F): 2.5 kΩ
80°C (176°F): 0.3 kΩ
LDIA0093E
Component
partsTerminals Remarks
4WD sole-
noid valve6
Ground
terminalApprox. 20°C (68°F): Approx. 3.0 - 3.4Ω
Clutch pres-
sure switch7In room temperature

2-4WD shift solenoid valve “OFF”: No conti-
nuity

2-4WD shift solenoid valve and transfer
motor “ON”: Continuity exists
Line pressure
switch1In room temperature

Turn ignition switch to “OFF” position and
leave vehicle for more than 5 minutes.
(OFF): No continuity

Transfer motor “ON”: Continuity exists
LDIA0094E