INFINITI QX4 2005 Factory Service Manual

TF-118
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connec-
tor E142 terminals 3 (B), 6 (B), E143 terminal 45 (B) and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
3. CHECK COMBINATION METER POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect combination meter harness connector.
3. Check voltage between combination meter harness connector
terminal and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between combination meter harness connector
terminal and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or
replace damaged parts.

10A fuse No. 14 located in the fuse block (J/B). Refer
to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

Harness for short or open between battery and combination meter harness connector M24 ter-
minal 24 (O/L).

Ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" . Continuity should exist.
SDIA2691E
Connector Terminal (Wire color) Voltage (Approx.)
M24 24 (O/L) - Ground 0V
WDIA0151E
Connector Terminal (Wire color) Voltage (Approx.)
M24 24 (O/L) - Ground Battery voltage
WDIA0152E

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-119
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Revision: October 20052005 QX56
4. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and combination meter harness connector.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E142 terminal 2 (B/W)
and combination meter harness connector M24 terminal 32 (B/
W).
–Transfer control unit harness connector E142 terminal 11 (L)
and combination meter harness connector M24 terminal 31 (L).
–Transfer control unit harness connector E142 terminal 12 (W/G)
and combination meter harness connector M24 terminal 33 (W/
G).
–Transfer control unit harness connector E142 terminal 21 (BR)
and combination meter harness connector M24 terminal 30
(BR).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK INDICATOR LAMP CIRCUIT
1. Connect combination meter harness connector.
2. Disconnect transfer control unit harness connector.
3. Turn ignition switch “ON”.
4. Ground the following terminals using suitable wiring.
–Transfer control unit harness connector E142 terminal 2 (B/W)
and ground.
–Transfer control unit harness connector E142 terminal 11 (L)
and ground.
–Transfer control unit harness connector E142 terminal 12 (W/G)
and ground.
–Transfer control unit harness connector E142 terminal 21 (BR)
and ground.
Do indicator lamps turn on?
OK >> GO TO 6.
NG >> Replace combination meter. Refer to IP-13, "
Combination Meter" .
6. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 7.Continuity should exist.
WDIA0160E
SDIA2772E

TF-120
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
7. 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 >> Inspection End.
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.

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-121
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Revision: October 20052005 QX56
4WD Warning Lamp Does Not Turn ONEDS002HN
SYMPTOM:
4WD warning lamp does not turn ON when turning ignition switch to “ON”.
DIAGNOSTIC PROCEDURE
1. CHECK TRANSFER CONTROL UNIT POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Connect transfer control unit harness connector.
3. Check voltage between transfer control unit harness connector
terminals and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between transfer control unit harness connector
terminals and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or replace damaged parts.

10A fuses No. 26 located in fuse and fusible link box and No. 59 located in the fuse and relay
box. Refer to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

20A fuse No. 53 located in the IPDM E/R. Refer to PG-4, "POWER SUPPLY ROUTING CIR-
CUIT" .

Harness for short or open between battery and transfer control unit harness connector termi-
nals 47.

Harness for short or open between battery and transfer control unit harness connector terminal
29.

Harness for short or open between battery and transfer shut off relay harness connector E69
terminal 1 (G), and 3 (G).

Harness for short or open between transfer shut off relay harness connector E69 terminal 2
(SB) and transfer control unit harness connector terminal 30.

Harness for short or open between transfer shut off relay harness connector E69 terminal 5 (Y/
R) and transfer control unit harness connector terminals 16 (Y/R) and 22 (Y/R).

Battery and ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" .

Transfer shut off relay. Refer to TF-57, "COMPONENT INSPECTION" .
Connector Terminal (Wire color) Voltage (Approx.)
E14216 (Y/R) - Ground
0V 22 (Y/R) - Ground
E14329 (L/W) - Ground
30 (SB) - Ground
Battery voltage
47 (W) - Ground
WDIA0165E
Connector Terminal (Wire color) Voltage (Approx.)
E14216 (Y/R) - Ground
Battery voltage 22 (Y/R) - Ground
E14329 (L/W) - Ground
30 (SB) - Ground 0V
47 (W) - Ground Battery voltage
WDIA0166E

TF-122
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
2. CHECK TRANSFER CONTROL UNIT GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check continuity between transfer control unit harness connec-
tor E142 terminals 3 (B), 6 (B), E143 terminal 45 (B) and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
3. CHECK COMBINATION METER POWER SUPPLY CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector.
3. Check voltage between combination meter harness connector
terminal and ground.
4. Turn ignition switch “ON”. (Do not start engine.)
5. Check voltage between combination meter harness connector
terminal and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following. If any items are damaged, repair or
replace damaged parts.

10A fuse No. 14 located in the fuse block (J/B). Refer
to PG-4, "
POWER SUPPLY ROUTING CIRCUIT" .

Harness for short or open between battery and combination meter harness connector M24 ter-
minal 24 (O/L).

Ignition switch. Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" . Continuity should exist.
SDIA2691E
Connector Terminal (Wire color) Voltage (Approx.)
M24 24 (O/L) - Ground 0V
WDIA0151E
Connector Terminal (Wire color) Voltage (Approx.)
M24 24 (O/L) - Ground Battery voltage
WDIA0152E

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-123
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Revision: October 20052005 QX56
4. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and combination meter harness connector.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E142 terminal 5 (W/B)
and combination meter harness connector M24 terminal 34 (W/
B).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK INDICATOR LAMP CIRCUIT
1. Connect combination meter harness connector.
2. Disconnect transfer control unit harness connector.
3. Turn ignition switch “ON”. (Do not start engine.)
4. Ground the following terminal using suitable wiring.
–Transfer control unit harness connector E142 terminal 5 (W/B)
and ground.
Does 4WD warning lamp turn on?
OK >> GO TO 6.
NG >> Replace combination meter. Refer to IP-13, "
Combina-
tion Meter" .
6. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 7.
7. 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 >> Inspection End.
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.
4WD Shift Indicator Lamp or 4LO Indicator Lamp Does Not ChangeEDS002HO
SYMPTOM:
4WD shift indicator lamp or 4LO indicator lamp does not change when switching 4WD shift switch.Continuity should exist.
WDIA0154E
SDIA2774E

TF-124
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE
1. CONFIRM THE SYMPTOM
Confirm 4WD shift indicator lamp and 4LO indicator lamp turn on when ignition switch is turned to ON.
Do 4WD shift indicator lamp and 4LO indicator lamp turn on?
YES >> GO TO 2.
NO >> Go to TF-117, "
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ON" .
2. CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to TF-62, "
4WD Shift Switch" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK SYSTEM FOR WAIT DETECTION SWITCH
Perform trouble diagnosis for wait detection switch system. Refer to TF-66, "
Wait Detection Switch" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4. CHECK SYSTEM FOR NEUTRAL-4LO SWITCH
Perform trouble diagnosis for neutral-4LO switch system. Refer to TF-59, "
Neutral-4LO Switch" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK SYSTEM FOR ATP SWITCH
Perform trouble diagnosis for ATP switch system. Refer to TF-113, "
AT P S w i t c h" .
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6. CHECK SYSTEM FOR 2-4WD SOLENOID
Perform trouble diagnosis for 2-4WD solenoid system. Refer to TF-91, "
2-4WD Solenoid" .
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
7. CHECK SYSTEM FOR TRANSFER CONTROL DEVICE
Perform trouble diagnosis for transfer control device system. Refer to TF-81, "
Transfer Control Device" .
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
8. CHECK SYSTEM FOR ACTUATOR MOTOR
Perform trouble diagnosis for actuator motor system. Refer to TF-70, "
Actuator Motor" .
OK or NG
OK >> GO TO 9.
NG >> Repair or replace damaged parts.

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-125
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9. CHECK SYSTEM FOR ACTUATOR POSITION SWITCH
Perform trouble diagnosis for actuator position switch system. Refer to TF-77, "
Actuator Position Switch" .
OK or NG
OK >> GO TO 10.
NG >> Repair or replace damaged parts.
10. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 11.
11 . 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 12.
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.
12. 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.
ATP Warning Lamp Turns ONEDS002HP
SYMPTOM:
ATP warning lamp turns ON when 4WD shift switch from “4H” to “4LO” or “4LO” to “4H” with A/T
selector lever “N” to “P” position.
DIAGNOSTIC PROCEDURE
1. CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to TF-50, "
Self-diagnostic Procedure" .
Do the self-diagnostic results indicate CAN communication?
YES >> Perform trouble diagnosis for CAN communication line. Refer to TF-113, "CAN Communication
Line" .
NO >> GO TO 2.
2. CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to TF-62, "
4WD Shift Switch" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK SYSTEM FOR PNP SWITCH SIGNAL
Perform trouble diagnosis for PNP switch signal system. Refer to TF-69, "
PNP Switch Signal (TCM)" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.

TF-126
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
4. CHECK SYSTEM FOR ATP SWITCH
Perform trouble diagnosis for ATP switch system. Refer to TF-113, "
AT P S w i t c h" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and combination meter harness connector.
3. Check continuity between the following terminals.
–Transfer control unit harness connector E142 terminal 15 (L/B)
and combination meter harness connector M24 terminal 6 (L/B).
–Transfer control unit harness connector E143 terminal 40 (L)
and combination meter harness connector M24 terminal 7 (R/B).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
6. CHECK ATP WARNING LAMP CIRCUIT
1. A/T selector lever in "P" position.
2. Connect combination meter harness connector and transfer control unit harness connector.
3. Disconnect ATP switch harness connector.
4. Ground the following terminal using suitable wiring.
–ATP switch harness connector F55 terminal 8 (L/Y) and ground.
5. Turn ignition switch “ON”. (Do not start engine.)
Does indicator lamp turn on?
OK >> GO TO 7.
NG >> Replace combination meter. Refer to IP-13, "
Combina-
tion Meter" . Continuity should exist.
WDIA0149E
40 to 7: Continuity should not exist.
7 to 40: Continuity should exist.
WDIA0150E
SDIA2769E

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-127
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Revision: October 20052005 QX56
7. SYMPTOM CHECK
Check again.
OK or NG
OK >> Inspection End.
NG >> GO TO 8.
8. 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 9.
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.
9. 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.
4LO Indicator Lamp Repeats FlashingEDS002HQ
SYMPTOM:
4LO lamp keeps flashing.
DIAGNOSTIC PROCEDURE
1. CONFIRM THE SYMPTOM
1. Set 4WD shift switch to “2WD”.
2. Move vehicle forward and backward, or drive straight increasing or decreasing under 20 km/h (12 MPH).
Does 4WD shift indicator lamp keep flashing?
YES >> GO TO 2.
NO >> Inspection End.
2. CHECK SYSTEM FOR WAIT DETECTION SWITCH
Perform trouble diagnosis for wait detection switch system. Refer to TF-66, "
Wait Detection Switch" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK SYSTEM FOR NEUTRAL-4LO SWITCH
Perform trouble diagnosis for neutral-4LO switch system. Refer to TF-59, "
Neutral-4LO Switch" .
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.