2008 INFINITI QX56 check engine

DLN-84
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
PHYSICAL VALUES
Terminal Layout
SHIFT AC MON2 [ON/
OFF]Check signal for transfer
control unit signal output • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• Brake pedal depressed 4WD shift switch: 4LO to
4H (Wait function is oper-
ating.)
ON
Except the above OFF
T/F F SPEED [km/h] or
[mph] Displayed, but do not use.
A/T R SPEED [km/h] or
[mph] Condition of vehicle
speed sensor A/T (Out-
put speed sensor)
During driving Approximately
matches the out-
put shaft speed.
AT GEAR POSI [1/2/3/4/
5] Condition of A/T selector
lever position
Displays actual A/T gear position. 1
2
3
4
5
Monitored item [Unit]
Content ConditionDisplay value
WDIA0378E
Te r m i n a lWire
color Item
ConditionData (Approx.)
1 GR 2-4WD shift solenoid valve • Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de- pressed 4WD shift switch: 2WD
0V
4WD shift switch: AUTO, 4H or 4LO Battery voltage
2 B/W 4WD shift indicator lamp
(2WD indica
tor lamp) 2WD indicator lamp: OFF
Battery voltage
2WD indicator lamp: ON 0V
3 B Ground Always0V
4 Y/L Transfer shift high relay • Vehicle stopped
• Engine running
• A/T selector lever
“N” position
• Brake pedal de-
pressed 4WD shift switch: 4H to 4LO (“Wait” func-
tion is operating.)
Battery voltage
Except the above 0V
5 W/B 4WD warning lamp 4WD warning lamp: ON
0V
4WD warning lamp: OFF Battery voltage
6 B Ground Always0V
7 L CAN-H ——
8 P CAN-L ——
9G/W 4WD shift switch
(2WD) Ignition switch: ON4WD shift switch: 2WD
Battery voltage
4WD shift switch: AUTO, 4H or 4LO 0V
Revision: March 2010 2008 QX56

DLN-100
< SYMPTOM DIAGNOSIS >[ATX14B]
4WD SYSTEM SYMPTOMS
SYMPTOM DIAGNOSIS
4WD SYSTEM SYMPTOMS
Symptom TableINFOID:0000000001737182
If 4WD warning lamp turns ON, perform self-diagnosis. Refer to DLN-18, "CONSULT-III Function (ALL MODE AWD/4WD)".
NOTE:
• Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not a
malfunction.
• Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is 4H or 4LO, steering wheel is turned fully to either side.
Symptom ConditionReference page
4WD shift indicator lamp and 4LO indicator lamp do not turn ON
(4WD shift indicator lamp and 4LO indicator lamp check) Ignition switch: ON
DLN-101
4WD warning lamp does not turn ON
(4WD warning lamp check) Ignition switch: ON
DLN-103
4WD shift indicator lamp or 4LO indicator lamp does not change Engine runningDLN-105
ATP warning lamp does not turn ON Engine runningDLN-107
4WD shift indicator lamp keeps flashing Engine runningDLN-109
4WD warning lamp flashes rapidly (2 times/second) While drivingDLN-110
4WD warning lamp flashes slowly
(1 time/2 seconds) While driving
DLN-111
Heavy tight-corner braking symptom occurs
(See NOTE.) • While driving
•AUTO mode
• Steering wheel is turned fully
to either side DLN-112
ATP switch does not operate
Engine runningDLN-114
4WD system does not operate While drivingDLN-116
Revision: March 2010 2008 QX56

4WD WARNING LAMP DOES NOT TURN ONDLN-103
< SYMPTOM DIAGNOSIS > [ATX14B]
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4WD WARNING LAMP DOES NOT TURN ON
DescriptionINFOID:0000000001737185
4WD warning lamp does not turn ON when turning ignition switch to ON.
Diagnosis ProcedureINFOID:0000000001737186
1.CHECK TRANSFER CONTROL UNIT PO WER SUPPLY AND GROUND CIRCUITS
Refer to DLN-22, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 2.
NO >> Repair as necessary.
2.CHECK COMBINATION METER POWER SUPPLY AND GROUND CIRCUITS
Refer to MWI-30, "
COMBINATION METER : Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Perform repairs as necessary.
3.CHECK HARNESS BETWEEN TR ANSFER CONTROL UNIT AND COMBINATION METER
1. Turn ignition switch OFF. (Stay for at least 5 seconds.)
2. Disconnect transfer control unit and combination meter harness connectors.
3. Check continuity between the following terminals.
- Transfer control unit harness connector E142 (A) terminal 5 and combination meter harness connector M23 (B) terminal 49.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.CHECK INDICATOR LAMP CIRCUIT
1. Connect combination meter harness connector.
2. Turn ignition switch ON. (Do not start engine.)
3. Ground the following terminal using suitable wiring.
- Transfer control unit harness connector E142 terminal 5 and ground.
Does 4WD warning lamp turn on?
YES >> GO TO 5.
NO >> Replace combination meter. Refer to MWI-76,
"Removal and Installation".
5.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 6.
6.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Continuity should exist.
AWDIA0187ZZ
SDIA2774E
Revision: March 2010
2008 QX56

DLN-108
< SYMPTOM DIAGNOSIS >[ATX14B]
ATP WARNING LAMP DOES NOT TURN ON
- Transfer control unit harness
connector E143 (B) terminal 40
and combination meter harness connector M23 (A) terminal 44.
Also check harness for short to ground and short to power.
Are the inspection results normal?
YES >> GO TO 6.
NO >> Repair or replace damaged parts.
6.CHECK ATP WARNING LAMP CIRCUIT
1. Place 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 and ground.
5. Turn ignition switch ON. (Do not start engine.)
Does indicator lamp turn on?
YES >> GO TO 7.
NO >> Replace combination meter. Refer to MWI-76, "
Removal
and Installation".
7.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 8.
8.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 9.
NO >> Check transfer control unit pin terminals fo r 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 DLN-140, "
Disassembly and Assembly".
2. Check transfer inner parts.
Are the inspection results normal?
YES >> Inspection End.
NO >> Repair or replace damaged parts. 40 to 44: Continuity should not exist.
44 to 40: Continuity should exist.
AWDIA0186ZZ
SDIA2769E
Revision: March 2010
2008 QX56

DLN-112
< SYMPTOM DIAGNOSIS >[ATX14B]
HEAVY TIGHT-CORNER BRAKING SYMPTOM OCCURS
HEAVY TIGHT-CORNER BR
AKING SYMPTOM OCCURS
DescriptionINFOID:0000000001737197
This symptom occurs when the vehicle is accelerati ng in 4WD and the steering wheel is turned fully either
direction. It may feel like a bump or being pushed fr om behind. A small amount of this bumping feeling is
acceptable under certain road conditions. The transfer case may be adjusted using the CONSULT-III to com-
pensate for this condition.
Diagnosis ProcedureINFOID:0000000001737198
DIAGNOSTIC PROCEDURE
NOTE:
• Light tight-corner braking symptom may occur depending on driving conditions in AUTO mode. This is not a malfunction.
• Heavy tight-corner braking symptom occurs when vehicle is driven in the following conditions: 4WD shift
switch is 4H or 4LO, steering wheel is turned fully to either side.
1.CHECK SYSTEM FOR CAN COMMUNICATION LINE
Perform self-diagnosis. Refer to DLN-18, "
CONSULT-III Function (ALL MODE AWD/4WD)".
Is CAN COMM CIRCUIT [U1000] displayed?
YES >> Perform trouble diagnosis for CAN communication line.
NO >> GO TO 2.
2.CHECK SYSTEM FOR 4WD SHIFT SWITCH
Perform trouble diagnosis for 4WD shift switch system. Refer to DLN-31, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK ACCELERATOR PEDAL POSITION SIGNAL CIRCUIT
Perform self diagnosis for ECM. Refer to EC-63, "
CONSULT-III Function (ENGINE)".
Is any malfunction deteced by self-diagnosis?
YES >> Check the malfunctioning system.
NO >> GO TO 4.
4.CHECK SYSTEM FOR CLUT CH PRESSURE SOLENOID
Perform trouble diagnosis for clutch pressure solenoid system. Refer to DLN-70, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 5.
NO >> Repair or replace damaged parts.
5.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 6.
6.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> GO TO 7.
NO >> Check transfer control unit pin terminals fo r damage or loose connection with harness connector.
If any items are damaged, repair or replace damaged parts.
7.CHECK TRANSFER INNER PARTS
1. Disassemble transfer assembly. Refer to DLN-140, "
Disassembly and Assembly".
2. Check transfer inner parts.
Revision: March 2010 2008 QX56

DLN-114
< SYMPTOM DIAGNOSIS >[ATX14B]
ATP SWITCH
ATP SWITCH
DescriptionINFOID:0000000001737199
The ATP indicator is ON when the transfer case is not in neutral.
Diagnosis ProcedureINFOID:0000000001737200
DIAGNOSTIC PROCEDURE
1.CHECK ATP SWITCH SIGNAL

With CONSULT-III
1. Start engine.
2. Select DATA MONITOR mode for ALL MODE AWD/4WD with CONSULT-III.
3. Read out the value of ATP SWITCH.
Without CONSULT-III
1. Start engine.
2. Check voltage between transfer control unit harness connector
terminal and ground.
Are inspection results normal?
YES >> GO TO 5.
NO >> 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 and ATP switch harness connector F55 ter-
minal 8.
Also check harness for short to ground and short to power.
Are inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK GROUND CIRCUIT
Condition Display value
• Vehicle stopped
• Engine running
• A/T selector lever N
• Brake pedal de- pressed 4WD shift switch
: 4H to 4LO or 4LO to 4H
(While actuator motor is operating.)
ON
Except the above OFF
Connector TerminalConditionVoltage
(Approx.)
E143 40 -
Ground • Vehicle stopped
• Engine running
• A/T selector lever
N
• Brake pedal de- pressed 4WD shift switch: 4H
to 4LO or 4LO to 4H
(While actuator motor
is operating.)
0V
Except the above Battery
voltage
SDIA2755E
Continuity should exist.
SDIA2756E
Revision: March 2010
2008 QX56

ATP SWITCHDLN-115
< SYMPTOM DIAGNOSIS > [ATX14B]
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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 and ground.
Also check harness for short to ground and short to power.
Are inspection results normal?
YES >> GO TO 4.
NO >> 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 DLN-16, "
Component Parts Location".
4. Push and release ATP switch and check continuity between ATP
switch terminals 8 and 9.
Are inspection results normal?
YES >> GO TO 5.
NO >> Replace ATP switch.
5.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are inspection results normal?
YES >> GO TO 6.
NO >> 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 >> Inspection End.
NO >> GO TO DLN-107, "
Diagnosis Procedure".
Continuity should exist.
SDIA2394E
Terminal
Condition Continuity
8 - 9 Push ATP switch
Yes
Release ATP switch No
SDIA2757E
Revision: March 2010 2008 QX56

PRECAUTIONSDLN-119
< PRECAUTION > [ATX14B]
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5. When the repair work is completed, return the ignition switch to the ″LOCK ″ position before connecting
the battery cables. (At this time, the steering lock mechanism will engage.)
6. Perform a self-diagnosis check of al l control units using CONSULT-III.
Precaution for Transfer Assembly and Transfer Control Unit ReplacementINFOID:0000000001737205
When replacing transfer assembly or transfer control uni t, check the 4WD shift indicator lamp as follows.
1. Turn ignition switch ON.
2. Check 4WD shift indicator lamp is turned ON for approximately 1 second.
• If OK, the position between transfer assembly and transfer control unit is correct.
• If NG, the position is different between transfer assembly and transfer control unit. Adjust the position between transfer assembly and transfer control unit. See METHOD FOR POSITION
ADJUSTMENT that follows.
METHOD FOR POSITION ADJUSTMENT
1. Start engine. Run the engine for at least 10 seconds.
2. Stop vehicle and move A/T selector lever to N position with brake pedal depressed. Stay in N for at least 2
seconds.
3. Turn 4WD shift switch to 2WD position. Stay in 2WD for at least 2 seconds.
4. Turn ignition switch OFF.
5. Start engine.
6. Erase self-diagnosis. Refer to DLN-18, "
CONSULT-III Function (ALL MODE AWD/4WD)".
7. Check 4WD shift indicator lamp. Refer to DLN-7, "
Preliminary Check".
If 4WD shift indicator lamp does not indicate 2WD, install new transfer control unit and retry the above
check.
PrecautionINFOID:0000000001737206
• Before connecting or disconnect ing the transfer control unit
harness connector, turn ignition switch “OFF” and disconnect
battery cables. Failure to do so may damage the transfer con-
trol unit. Battery voltage is ap plied to transfer control unit
even if ignition swit ch is turned “OFF”.
• When connecting or disconnecting pin connectors into or
from transfer control unit, take care not to damage pin termi-
nals (bend or break).
When connecting pin connectors make sure that there are not
any bends or breaks on transfer control unit pin terminals.
SEF289H
SEF291H
Revision: March 2010 2008 QX56