INFINITI QX56 2004 Factory Service Manual

TF-56
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
Revision: August 20072004 QX56
114WD shift indicator lamp
(4H)“4H” indicator lamp comes ON. Less than 1V
4WD shift switch is set to any posi-
tion other than 4H.Battery voltage
124WD shift indicator lamp
(4LO)“4LO” indicator lamp comes ON. 0V
4WD shift switch is set to any posi-
tion other than 4LO.Battery voltage
13 Transfer shift relay (Low)
&While actuator is operating (4LO →
4H)Battery voltage
Actuator does not operate. 0V
14 Transfer motor relayTransfer motor relay is ON. Battery voltage
Transfer motor relay is OFF. Less than 1V
15 ATP lampAT selector lever is set to P position. Battery voltage
AT selector lever is set to any posi-
tion other than P.0V
16 Power supply —Ignition key is set to ON position. Battery voltage
Ignition key is set to OFF position. 0V
18 4WD shift switch (4H)
&4WD shift switch is set to 4H posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than 4H.Less than 1V
19 4WD solenoid valve4WD shift switch is set to AUTO posi-
tion.1.5 - 3V
4WD shift switch is set to any posi-
tion other than 2WD.Less than 1V
214WD shift indicator lamp
(AUTO)“AUTO” indicator lamp comes ON. 0V
4WD shift switch is set to any posi-
tion other than AUTO.Battery voltage
22 Power supply —Ignition key is set to ON position. Battery voltage
Ignition key is set to OFF position. 0V
23 4WD shift switch (4LO)
&4WD shift switch is set to 4LO posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than 4LO.Less than 1V
24 4WD shift switch (AUTO)4WD shift switch is set to AUTO posi-
tion.Battery voltage
4WD shift switch is set to any posi-
tion other than AUTO.Less than 1V
25 Neutral-4LO switchTransfer is set to 4LO position. 0V
Transfer is set to any position other
than 4LO.Battery voltage
27Transfer 4H actuator
switch4WD shift switch is set to 4H posi-
tion.Less than 1V
4WD shift switch is set to any posi-
tion other than 4H.Battery voltage
28 Sensor ground — Less than 1V Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)

TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
TF-57
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Revision: August 20072004 QX56
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-58
TROUBLE DIAGNOSIS — GENERAL DESCRIPTION
Revision: August 20072004 QX56
*3: While wait detection system is operating, terminal 43 has battery voltage.47Power supply (memory
back up)— — Battery voltage
48 CONSULT-II (TX) — — — Te r m i n a l
No.Item ConditionJudgement standard
(Approx.)

DTC U1000, U1001 CAN COMMUNICATION LINE
TF-59
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Revision: August 20072004 QX56
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

4WD SOLENOID VALVE
TF-61
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Revision: August 20072004 QX56
4. PERFORM SELF-DIAGNOSIS
After driving for a while, perform self-diagnosis.
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.

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
TF-63
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Revision: August 20072004 QX56
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

TF-64
TRANSFER MOTOR AND TRANSFER MOTOR RELAY
Revision: August 20072004 QX56
TRANSFER MOTOR AND TRANSFER MOTOR RELAYPFP:00000
Diagnostic ProcedureEDS00185
1. CHECK TRANSFER MOTOR AND TRANSFER MOTOR RELAY
Refer to TF-96, "
TRANSFER MOTOR" and TF-97, "TRANSFER
MOTOR RELAY" .
OK or NG
OK >> GO TO 2.
NG >> Replace transfer motor or transfer motor relay.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Select “MAIN SIGNALS” in Data Monitor.
2. Read out ON/OFF status of “MOTOR RELAY”.
3. When the value is different from standard value although ON/
OFF switching occurs, check the following items.

PNP switch and throttle position sensor circuits
Refer to AT-109, "
DTC P0705 PARK/NEUTRAL POSITION
SWITCH" , AT-129, "DTC P1705 THROTTLE POSITION SEN-
SOR" .
OK or NG
OK >> GO TO 3.
NG >> 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.
3. CHECK TRANSFER MOTOR RELAY POWER SOURCE
1. Disconnect transfer motor relay harness connectors E153 and
E154.
2. Turn ignition switch to ON position.
3. Check voltage between transfer motor relay harness connector
E153 terminal 5 (G/R), E154 terminal 2 (Y/R), and ground.
OK or NG
OK >> GO TO 4.
NG >> Check the following.

No. 58 fuse (20A)

No. 49 fuse (10A)

Harness continuity between ignition switch and No. 58 fuse (20A) and No. 49 fuse (10A).

Harness continuity between fuse and transfer motor relay.
LDIA0102E
SMT975D
Voltage : Battery voltage
LDIA0070E

TRANSFER MOTOR AND TRANSFER MOTOR RELAY
TF-65
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Revision: August 20072004 QX56
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