Ins INFINITI QX56 2004 Factory Service Manual

TF-76
DATA ERASE/DISPLAY
Revision: August 20072004 QX56
DATA ERASE/DISPLAYPFP:00000
Diagnostic ProcedureEDS0018A
1. CHECK TRANSFER CONTROL UNIT POWER SOURCE
1. Turn ignition switch to OFF position and perform self-diagnosis
again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and
TF-31, "
Trouble Diagnosis with CONSULT-II" .
2. Turn ignition switch to OFF position.
3. Disconnect transfer control unit harness connector E143.
4. Check voltage between transfer control unit harness connector
E143 terminal 47 (W) and ground.
OK or NG
OK >> GO TO 2.
NG >> Check the following.

No. 53 fuse (20A)

Harness continuity between fuse and transfer control unit
2. PERFORM SELF-DIAGNOSIS AGAIN
After driving for a while, perform self-diagnosis again.
Refer to TF-27, "
Trouble Diagnosis without CONSULT-II" and 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. Voltage : Battery voltage
LDIA0078E

SHIFT ACTUATOR
TF-79
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B
TF
Revision: August 20072004 QX56
6. CHECK HARNESS CONTINUITY BETWEEN TRANSFER CONTROL UNIT AND TRANSFER CON-
TROL DEVICE
OK or NG
OK >> GO TO 7.
NG >> Repair and replace harness connector between transfer control unit and transfer control device.
7. 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/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.

SHIFT ACTUATOR POSITION SWITCH
TF-81
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TF
Revision: August 20072004 QX56
5. CHECK INPUT SIGNAL
Without CONSULT-II
1. Start engine (idling).
2. Check voltage transfer control unit harness connector E143 ter-
minal 27 (W/L) [or 44 (LG/B)] and ground while 4WD shift switch
is set from 4H to 4LO (or from 4LO to 4H).
3. Result
OK or NG
OK >> GO TO 6.
NG >> Check the following.

Continuity between transfer control unit and transfer control device.

Check ground circuit between transfer control device and ground.
6. 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/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.
SMT830D
Terminal ConditionVo l ta g e
(Approx.)
274WD shift switch is
set to 4HLess than 1V
4WD shift switch is
set except 4HBattery voltage
444WD shift switch is
set to 4LOLess than 1V
4WD shift switch is
set except 4LOBattery voltage

TF-84
SHIFT ACTUATOR CIRCUIT
Revision: August 20072004 QX56
6. CHECK INPUT SIGNAL
Without CONSULT-II
1. Start engine (idling).
2. Check voltage between transfer control unit harness connector
E142 terminal 4 (Y/L) [or 13 (G/B)] and ground while 4WD shift
switch is set from 4H to 4LO (or from 4LO to 4H).
3. Result
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7. CHECK HARNESS CONTINUITY BETWEEN TRANSFER CONTROL UNIT AND TRANSFER SHIFT
HIGH AND LOW RELAYS
OK or NG
OK >> GO TO 8.
NG >> Repair and replace harness connector between transfer control unit and transfer shift HIGH or
LOW relay.
8. 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/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.
LDIA0083E
Terminal ConditionVo l ta g e
(Approx.)
4While actuator is
operating for 4H to
4LOBattery voltage
Actuator does not
operate0V
13While actuator is
operating for 4LO to
4HBattery voltage
Actuator does not
operate0V

TF-86
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connectors E142 and
E143.
3. Measure resistance between transfer control unit harness con-
nectors E142 and E143 terminals 3(B), 6(B), 45(B) and ground.
OK or NG
OK >> GO TO 3.
NG >> Check continuity between transfer control unit and
ground.
3. CHECK PROCEDURES FROM THE BEGINNING AGAIN
Check again.
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. Resistance : Continuity should exist.
LDIA0087E

TROUBLE DIAGNOSES FOR SYMPTOMS
TF-87
C
E
F
G
H
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K
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MA
B
TF
Revision: August 20072004 QX56
Symptom 2. 4WD Warning Lamp Does Not Turn ON (Although the ignition
switch is turned ON, the 4WD warning lamp does not turn ON)
EDS0018F
1. CHECK TRANSFER CONTROL UNIT POWER SOURCE
1. Turn ignition switch to OFF position and disconnect transfer control unit harness connector E142.
2. Turn ignition switch to ON position (do not start engine).
3. Check voltage between transfer control unit harness connector
E142 terminals 16 (Y/R), 22 (Y/R) and ground.
OK or NG
OK >> GO TO 2.
NG >> Check the following.

Continuity between ignition switch and transfer con-
trol unit

Ignition switch and No. 49 fuse (10A)
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch to OFF position.
2. Disconnect transfer control unit harness connectors E142 and
E143.
3. Measure resistance between transfer control unit harness con-
nectors E142 and E143 terminals 3 (B), 6 (B), 45 (B) and
ground.
OK or NG
OK >> GO TO 3.
NG >> Check continuity between transfer control unit and
ground.
3. CHECK 4WD WARNING LAMP CIRCUIT AND COMBINATION METER
Check the following.

Combination meter. Refer to DI-17, "How to Proceed With Trouble Diagnosis" .

Continuity between ignition switch and combination meter

Continuity between combination meter and transfer control unit
OK or NG
OK >> Replace transfer control unit. Refer to TF-98, "Removal and Installation" .
NG >>

Repair or replace harness or connector.

Replace combination meter. Refer to DI-25, "Removal and Installation of Combination Meter" .
WDIA0080E
Voltage : Battery voltage
LDIA0089E
Resistance : Continuity should exist.
LDIA0087E

TF-88
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
Symptom 3. 4WD Shift Indicator Lamp Does Not Turn OFF (When 4WD shift
switch is set from 4H to 4LO, all the 4WD shift indicator lamps do not turn off)
EDS0018G
1. CHECK ATP SWITCH CIRCUIT
Check ATP switch circuit.
Refer to TF-69, "
Diagnostic Procedure" .
OK or NG
OK >> GO TO 2.
NG >> Check, repair or replace faulty parts.
2. CHECK PROCEDURE FROM THE BEGINNING AGAIN
Check again.
OK or NG
OK >> Inspection End.
NG >> Recheck each connector pin terminals for damage or loose connection.
WDIA0071E

TROUBLE DIAGNOSES FOR SYMPTOMS
TF-89
C
E
F
G
H
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J
K
L
MA
B
TF
Revision: August 20072004 QX56
Symptom 4. ATP Warning Lamp Does Not Turn ON (When 4WD shift switch is
set from 4H to 4LO with the A/T selector lever in P position, the ATP warning
lamp does not turn on)
EDS0018H
1. CHECK ATP SWITCH CIRCUIT
Check ATP switch circuit.
Refer to TF-69, "
ATP SWITCH, WAIT DETECTION SWITCH AND
NEUTRAL-4LO SWITCH" .
OK or NG
OK >> GO TO 2.
NG >> Check, repair or replace faulty parts.
2. CHECK COMBINATION METER
Check the combination meter. Refer to DI-17, "
How to Proceed With Trouble Diagnosis"
OK or NG
OK >> Replace transfer control unit. Refer to TF-98, "Removal and Installation" .
NG >> Replace combination meter. Refer to DI-25, "
Removal and Installation of Combination Meter" .
WDIA0103E

TROUBLE DIAGNOSES FOR SYMPTOMS
TF-91
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: August 20072004 QX56
3. CHECK 4LO INDICATOR LAMP CIRCUIT AND COMBINATION METER
Check the following.

Combination meter. Refer to DI-17, "How to Proceed With Trouble Diagnosis" .

Continuity between ignition switch and combination meter

Continuity between combination meter and transfer control unit

Condition of ATP and neutral-4LO switch circuit. Refer to TF-69, "ATP SWITCH, WAIT DETECTION
SWITCH AND NEUTRAL-4LO SWITCH" .
OK or NG
OK >> Replace transfer control unit. Refer to TF-98, "Removal and Installation" .
NG >>

Repair or replace harness or connector.

Replace combination meter. Refer to DI-25, "Removal and Installation of Combination Meter" .

Replace ATP or neutral-4LO switch.
Symptom 6. 4WD Shift Indicator Lamp Does Not Indicate “LOCK” (When 4WD
shift switch is set to “4H”, 4WD shift indicator lamp does not indicate “LOCK”)
EDS0018J
1. CHECK 4WD WARNING LAMP
Is 4WD warning lamp turned ON?
Ye s o r N o
Yes >> Refer to TF-27, "Trouble Diagnosis without CONSULT-
II" .
No >> GO TO 2.
2. CHECK NEUTRAL-4LO, WAIT DETECTION AND ATP SWITCH CIRCUITS
Check neutral-4LO, wait detection and ATP switch circuits. Refer to TF-69, "
ATP SWITCH, WAIT DETECTION
SWITCH AND NEUTRAL-4LO SWITCH" .
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.
WDIA0071E

TF-92
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: August 20072004 QX56
Symptom 7. 4WD Shift Indicator Lamp Repeats Flickering (4WD Shift Indicator
Lamp Keeps Flickering)
EDS0018K
1. CHECK 4WD SHIFT INDICATOR LAMP
1. Set 4WD shift switch to 2WD position.
2. Move vehicle forward and backward. Or drive straight increasing
or decreasing speed under 20 km/h (12 MPH).
3. Does 4WD shift indicator lamp keep flickering?
Ye s o r N o
Yes >> GO TO 2.
No >> Inspection End.
2. CHECK TIGHT CORNER BRAKING SYMPTOM
Drive vehicle at speed under 20 km/h (12 MPH), turning steering wheel to the limit. Does tight corner braking
symptom occur?
Ye s o r N o
Yes >> GO TO 3.
No >> GO TO 4.
3. CHECK 4WD SHIFT INDICATOR LAMP
Does the 4WD shift indicator lamp keep flickering when the front wheels are jacked up?
Ye s o r N o
Yes >> Check transfer unit operating system.
No >> Check tires.
4. CHECK 4WD WARNING LAMP
Does 4WD warning lamp flicker? (4WD shift indicator lamp is turned OFF.)
Ye s o r N o
Yes >> Perform self-diagnosis. Refer to TF-27, "Trouble Diagnosis without CONSULT-II" .
No >> GO TO 5.
5. CHECK 4WD SHIFT INDICATOR LAMP
Does 4WD shift indicator lamp keep flickering?
Ye s o r N o
Yes >> Check again.
No >> Inspection End.
WDIA0071E