fluid INFINITI QX56 2004 Factory Service Manual

TF-44
TROUBLE DIAGNOSIS — INTRODUCTION
Revision: August 20072004 QX56
TROUBLE DIAGNOSIS — INTRODUCTIONPFP:00000
IntroductionEDS0017W
DESCRIPTION
When a malfunction (indicated by the 4WD warning lamp illumination) occurs, collect information first from the
customer about how the malfunction occurs. Then, proceed with the diagnosis presuming it is the cause. Also
inspect the electrical system, paying close attention to other possibilities such as fluid level and leaks.
All-mode 4WD transfer is controlled by transfer control unit and sensors.
If a malfunction occurs in the all-mode 4WD system, the 4WD warning lamp lights up to inform of the system
malfunction. There are two ways to identify the cause of the malfunction.
1. Performing the self-diagnosis. (The 4WD warning lamp will indicate what kind of malfunction has occurred
by flickering.)
2. Performing diagnosis using CONSULT-II.
DIAGNOSTIC WORKSHEET
Information from Customer
KEY POINTS

WHAT ..... Vehicle model

WHEN..... Date, Frequencies

WHERE..... Road conditions

HOW..... Operating conditions, Symptoms
Diagnostic Worksheet
Information sheet from customer
Customer name MR/MS Model & Year VIN
Transfer model
AT X 1 4 BEngine Mileage
Incident Date Manuf. Date In Service Date
Frequency❏ Continuous ❏ Intermittent ( times a day)
Symptoms❏ 4WD shift indicator lamp does not turn on.
❏ 4WD warning lamp does not turn on.
❏ 4WD shift indicator lamp does not turn off.
❏ ATP warning lamp does not turn on.
❏ 4LO indicator lamp does not turn on.
❏ 4WD shift indicator lamp does not indicate “4H”.
❏ 4WD shift indicator lamp repeats flicking.
❏ Tight corner braking symptom occurs.
❏ 4WD system does not operate.
❏ Others.
4WD warning lamp❏ Continuously lit❏ Not lit
1.❏ Listen to customer complaints.TF-47
2.❏ Check transfer fluid.TF-47
❏ Leakage
❏ Fluid condition
❏ Fluid level
3.❏ Road testingTF-47
❏ 1. Check before engine is started.
❏ 2. Check at idle.
❏ 3. Cruise test
4.❏ Perform self-diagnosis NG items (with CONSULT-II and without CONSULT-II).TF-31
, TF-28

TROUBLE DIAGNOSIS — BASIC INSPECTION
TF-47
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TROUBLE DIAGNOSIS — BASIC INSPECTIONPFP:00000
Listen to Customer ComplaintsEDS0017Y

Each customer feels differently about a problem. It is important to fully understand the symptoms or condi-
tions for a customer complaint.

Listen to the customer about how and when the malfunction occurs, and make good use of it when per-
forming the road test.
Transfer Fluid CheckEDS0017Z

Check fluid for leaks and fluid level. Refer to TF-47, "Transfer Fluid Check" .
Road TestEDS00180
PREPARATION FOR ROAD TEST

The purpose of the test is to determine overall performance of
transfer and analyze causes of problems.

When a malfunction is found in any part of transfer, perform the
road test to locate the malfunction area and repair the malfunc-
tion parts.

The road test consists of the following three parts:
1. Check before engine is started
2. Check at idle
3. Cruise test

Perform road test and place checks for NG items on the diag-
nostic worksheet. Refer to TF-44, "
Diagnostic Worksheet" .
SMT089D

TROUBLE DIAGNOSIS — BASIC INSPECTION
TF-53
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Revision: August 20072004 QX56
3. CRUISE TEST
1. INSPECTION START
Do you have CONSULT-II?
Ye s o r N o
Yes >> GO TO 2.
No >> GO TO 3.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Warm up engine to normal operating temperature.
2. Park vehicle on flat surface.
3. Set 4WD shift switch to 4H position.
4. Set 4WD shift switch to AUTOposition.
5. Start engine.
6. Drive for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
(Drive vehicle until “FLUID TEMP SE” exceeds 0.9V.)
7. Park vehicle on flat surface.
8. Set 4WD shift switch to 2WD position.
9. Leave vehicle for at least 80 seconds with “FLUID TEMP SE” at
0.9V or less.
10. Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> Perform self-diagnosis. Refer to TF-31, "Trouble Diag-
nosis with CONSULT-II" .
No >> GO TO 4.
3. CHECK INPUT SIGNAL
Without CONSULT-II
1. Warm up engine to normal operating temperature.
2. Park vehicle on flat surface.
3. Set 4WD shift switch to 4H position.
4. Set 4WD shift switch to AUTO position.
5. Start engine.
6. Drive vehicle for at least 30 seconds at a speed higher than 20 km/h (12 MPH).
7. Park vehicle on flat surface.
8. Set 4WD shift switch to 2WD position.
9. Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> Perform self-diagnosis. Refer to TF-27, "Trouble Diagnosis without CONSULT-II" .
No >> GO TO 4.
SMT972D

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-57
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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-62
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Revision: August 20072004 QX56
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCHPFP:00000
Diagnostic ProcedureEDS00184
1. CHECK 2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
Refer to TF-95, "
2-4WD SHIFT SOLENOID VALVE AND TRANS-
FER FLUID TEMPERATURE SENSOR" and TF-95, "4WD SHIFT
SWITCH" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace 2-4WD shift solenoid valve or 4WD
shift switch.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “ECU INPUT SIGNALS” in Data Monitor.
2. Read out ON/OFF status of “2WD SW” and “LOCK SWITCH”.
OK or NG
OK >> 1. Perform transfer control unit input/output signal
inspection. Refer to TF-55, "
TRANSFER CONTROL
UNIT INSPECTION TABLE" .
2. If NG, recheck transfer control unit pin terminals for
damage or loose connection with harness connector.
NG >> GO TO 3.
SMT778D
SMT974D

TF-66
TRANSFER FLUID TEMPERATURE SENSOR
Revision: August 20072004 QX56
TRANSFER FLUID TEMPERATURE SENSORPFP:00000
Diagnostic ProcedureEDS00186
1. CHECK TRANSFER FLUID TEMPERATURE SENSOR
Refer to TF-95, "
2-4WD SHIFT SOLENOID VALVE AND TRANSFER FLUID TEMPERATURE SENSOR" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace fluid temperature sensor.
2. CHECK INPUT SIGNAL
Do you have CONSULT-II?
Ye s o r N o
Yes >> GO TO 3.
No >> GO TO 4.

TRANSFER FLUID TEMPERATURE SENSOR
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3. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in Data Monitor.
3. Read out the value of “FLUID TEMP SE”.
OK or NG
OK >> GO TO 5.
NG >> Check the following.

Continuity between transfer control unit and transfer terminal cord assembly harness connectorVo l ta g e
20°C (68°F) : Approx. 1.1V
80°C (176°F) : Approx. 0.3V
SMT784D
SMT974D

TF-68
TRANSFER FLUID TEMPERATURE SENSOR
Revision: August 20072004 QX56
4. CHECK INPUT SIGNAL
Without CONSULT-II
1. Turn ignition switch to ON position.
2. Check voltage between transfer control unit harness connector
E143 terminals 28 (B/G) and 31(G).
OK or NG
OK >> GO TO 5.
NG >> Check the following.

Continuity between transfer control unit and transfer
terminal cord assembly harness connector
5. PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-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.Vo l ta g e
20°C (68°F) : Approx. 1.1V
80°C (176°F) : Approx. 0.3V
LDIA0072E

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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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