Air INFINITI QX56 2004 Factory Service Manual

TROUBLE DIAGNOSIS — INTRODUCTION
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5.❏ Check component. Repair or replace the damaged parts.TF-109
6.❏ Perform final check. Perform road test (1 through 3).TF-47

TF-46
TROUBLE DIAGNOSIS — INTRODUCTION
Revision: August 20072004 QX56
Work FlowEDS0017X
HOW TO PERFORM TROUBLE DIAGNOSES FOR QUICK AND ACCURATE REPAIR
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a problem. It is important to fully understand the symptoms or
conditions for a customer complaint.
Make good use of the two sheets provided, “Information from Customer” (Refer to TF-44
) and “Diagnostic
Worksheet” (Refer to TF-44
), to perform the best troubleshooting possible.
*1:TF-47*2:TF-47*3:TF-47
*4:TF-85 - TF-94*5:TF-60 - TF-82*6:TF-47
WDIA0102E

TROUBLE DIAGNOSIS — BASIC INSPECTION
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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

DTC U1000, U1001 CAN COMMUNICATION LINE
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DTC U1000, U1001 CAN COMMUNICATION LINEPFP:23710
CAN Communication System InspectionEDS00182
INSPECTION PROCEDURE
1. PERFORM SELF-DIAGNOSIS
Perform transfer control unit self-diagnosis.
Is
“CAN COMM CIRCUIT” displayed in the self-diagnosis display items?
Yes >> Print out the self-diagnosis results and go to 2.
No >> Inspection End.
2. CONNECTOR INSPECTION
1. Disconnect the transfer control unit connectors E142 and E143.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace as necessary.
3. CAN COMMUNICATION SYSTEM CHECK
Check the data monitor item “CAN Diagnosis Support Monitor”.
>> After printing out the monitor items, go to CAN system. Refer to LAN-3, "
Precautions When Using
CONSULT-II" .

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-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

2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT SWITCH
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3. CHECK 4WD SHIFT SWITCH POWER SOURCE
1. Disconnect 4WD shift switch harness connector.
2. Turn ignition switch to ON position.
3. Check voltage between 4WD shift switch harness connector ter-
minal 1 and body ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following.

No. 49 fuse (10A)

Continuity between ignition switch and 4WD shift
switch
4. CHECK HARNESS CONTINUITY
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connector E142.
3. Check continuity between the following terminals.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or 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. Voltage : Battery voltage
SMT852D
Connec-
torTe r m i n a l
(Wire
color)Connec-
torTe r m i na l
(Wire
color)Continu-
ity
M141
(2WD)2 (G/W)
E1429 (G/W)
Yes M141
(4H)5 (O) 18 (O)
M141
(AUTO)3 (LG/R) 24 (LG/R)
M141
(4LO)6 (R) 23 (R)
M141 4 (G/R) 1 (GR)
LDIA0069E

TRANSFER MOTOR AND TRANSFER MOTOR RELAY
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4. CHECK HARNESS CONTINUITY
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connectors E142 and
E143, and transfer motor harness conector F57.
3. Check continuity between the following terminals.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace harness or connector.
5. PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" or TF-31, "Trouble Diagnosis with 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. Connec-
torTe r m i n a l
(Wire
color)Connec-
torTe r m i na l
(Wire
color)Continu-
ity
F57 14 (R)
E143 41 (R)
Yes E153 3 (R)
E154 1 (LG) E142 14 (LG)
Ground — F57 15 (B)
LDIA0071E

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.

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.