2005 INFINITI QX4 engine

TROUBLE DIAGNOSIS FOR SYSTEM
TF-113
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: October 20052005 QX56
CAN Communication LineEDS002IQ
DIAGNOSTIC PROCEDURE
1. CHECK CAN COMMUNICATION CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON” and start engine.
2. Select “SELF-DIAG RESULTS” mode for “ALL MODE AWD/4WD” within CONSULT-II.
3. Perform the self-diagnosis.
Is the
“CAN COMM CIRCUIT [U1000]” displayed?
YES >> Print CONSULT-II screen and go to LAN-3, "Precautions
When Using CONSULT-II" .
NO >> Inspection End.
ATP SwitchEDS002IR
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Data are reference value.
TRANSFER CONTROL UNIT TERMINALS AND REFERENCE VALUE
Data are reference value and are measured between each terminal and ground.
CAUTION:
When using a circuit tester to measure voltage for inspection, be sure not to extend forcibly any connector terminals.
SDIA1850E
Monitored item [Unit] Content Condition Display value
ATP SWITCH [ON/OFF] Condition of ATP switch

Vehicle stopped

Engine running

A/T selector lever “N"

Brake pedal depressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is
operating.) ON
Except the above OFF
Te r m i n a lWire
colorItem Condition Data (Approx.)
40 L ATP switch

Vehicle stopped

Engine running

A/T selector
lever “N"

Brake pedal
depressed4WD shift switch: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)0V
Except the above Battery voltage

TF-114
TROUBLE DIAGNOSIS FOR SYSTEM
Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE
1. CHECK ATP SWITCH SIGNAL
With CONSULT-II
1. Start engine.
2. Select “DATA MONITOR” mode for “ALL MODE AWD/4WD” with CONSULT-II.
3. Read out the value of “ATP SWITCH”.
Without CONSULT-II
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TRANSFER CONTROL UNIT AND ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit harness connector and the ATP switch harness connector.
3. Check continuity between transfer control unit harness connec-
tor E143 terminal 40 (L) and ATP switch harness connector F55
terminal 8 (L/Y).
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
Condition Display value

Vehicle stopped

Engine running

A/T selector lever
“N"

Brake pedal
depressed4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.) ON
Except the above OFF
SDIA2391E
ConnectorTe r m i n a l
(Wire
color)ConditionVoltage
(Approx.)
E14340 (L) -
Ground

Vehicle stopped

Engine running

A/T selector lever
“N"

Brake pedal
depressed4WD shift switch: 4H
to 4LO or 4LO to 4H
(While actuator motor
is operating.)0V
Except the aboveBattery
voltageSDIA2755E
Continuity should exist.
SDIA2756E

TROUBLE DIAGNOSIS FOR SYSTEM
TF-115
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: October 20052005 QX56
3. CHECK GROUND CIRCUIT
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Check continuity between ATP switch harness connector F55
terminal 9 (B) and ground.
Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
4. CHECK ATP SWITCH
1. Turn ignition switch “OFF”. (Stay for at least 5 seconds.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts" .
4. Push and release ATP switch and check continuity between ATP
switch terminals 8 and 9.
OK or NG
OK >> GO TO 5.
NG >> Replace ATP switch. Refer to TF-22, "
Location of Elec-
trical Parts" .
5. 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 6.
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.
6. CHECK ATP WARNING LAMP
1. Turn ignition switch “ON”. (Do not start engine.)
2. Move A/T selector lever to "P" position.
3. Set 4WD shift switch from "4H" to "4LO" or "4LO" to "4H".
Does ATP warning lamp turn ON while switching?
YES >> GO TO TF-125, "ATP Warning Lamp Turns ON" .
NO >> Inspection End.
COMPONENT INSPECTION
1. Turn ignition switch “OFF”. (Stay for at least 5 second.)
2. Disconnect ATP switch harness connector.
3. Remove ATP switch. Refer to TF-22, "
Location of Electrical Parts" . Continuity should exist.
SDIA2394E
Terminal Condition Continuity
8 - 9Push ATP switch Yes
Release ATP switch No
SDIA2757E

TROUBLE DIAGNOSIS FOR SYMPTOMS
TF-117
C
E
F
G
H
I
J
K
L
MA
B
TF
Revision: October 20052005 QX56
TROUBLE DIAGNOSIS FOR SYMPTOMSPFP:00007
4WD Shift Indicator Lamp and 4LO Indicator Lamp Do Not Turn ONEDS002HM
SYMPTOM:
4WD shift indicator lamp and 4LO indicator lamp do not turn ON for approx. 1 second 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 2.
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-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-121
C
E
F
G
H
I
J
K
L
MA
B
TF
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
C
E
F
G
H
I
J
K
L
MA
B
TF
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