air condition INFINITI QX56 2008 Factory Service Manual

DLN-80
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
ECU DIAGNOSIS
TRANSFER CONTROL UNIT
Reference ValueINFOID:0000000001737179
VALUE ON THE DIAGNOSIS TOOL
CONSULT-III data monitor item
Monitored item [Unit]
Content ConditionDisplay value
VHCL/S SEN·FR [km/h]
or [mph] Wheel speed (Front
wheel) Vehicle stopped
0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
VHCL/S SEN·RR [km/h]
or [mph] Wheel speed (Rear
wheel) Vehicle stopped
0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
ENGINE SPEED [rpm] Engine speed Engine stopped
(Engine speed: Less than 400 rpm)
0 rpm
Engine running
(Engine speed: 400 rpm or more) Approximately
equal to the indica-
tion on tachometer
THRTL POS SEN [V] Accelerator
pedal posi-
tion (APP) sensor signal
voltage Accelerator pedal: Released
Approx. 0.5V
Accelerator pedal: Fully depressed Approx. 4.0V
FLUID TEMP SE [V] Transfer fluid tempera-
ture signal voltage Transfer fluid temperature approx. 20 - 80
°C (68 - 176 °F) Approx. 1.1 - 0.3V
BATTERY VOLT [V] Power supply voltage for
transfer control unit Ignition switch: ON
Battery voltage
2WD SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 2WD
ON
4WD shift switch: AUTO, 4H or 4LO OFF
AUTO SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: AUTO
ON
4WD shift switch: 2WD, 4H or 4LO OFF
LOCK SWITCH [ON/
OFF] Input condition from 4WD
shift switch 4WD shift switch: 4H
ON
4WD shift switch: 2WD, AUTO or 4LO OFF
4L SWITCH [ON/OFF] Input condition from 4WD
shift switch 4WD shift switch: 4LO
ON
4WD shift switch: 2WD, AUTO or 4H OFF
N POSI SW TF [ON/
OFF] Condition of neutral-4LO
switch • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• Brake pedal depressed 4WD shift switch: 2WD,
AUTO or 4H
OFF
4WD shift switch: 4H to
4LO (While actuator mo-
tor is operating.) OFF
→ON
4WD shift switch: 4LO to
4H (While actuator motor
is operating.) ON
→OFF
4WD shift switch: 4LO ON
Revision: March 2010 2008 QX56

DLN-82
< ECU DIAGNOSIS >[ATX14B]
TRANSFER CONTROL UNIT
VHCL/S COMP [km/h] or
[mph]Vehicle speed Vehicle stopped
0 km/h (0 mph)
Vehicle running
CAUTION:
Check air pressure of tire under standard condition. Approximately
equal to the indica-
tion on speedome-
ter (Inside of
±
10%)
COMP CL TORQ [kgm] Condition of control
torque • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• Brake pedal depressed 4WD shift switch: 2WD 0 kg-m
4WD shift switch: AUTO
39 - 1,353 N·m
(4 - 138 kg-m, 29 - 998 ft-lb)
4WD shift switch: 4H or
4LO 1,353 N·m
(138 kg-m, 998 ft-
lb)
DUTY SOLENOID [%] Condition of clutch pres-
sure solenoid • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• Brake pedal depressed 4WD shift switch: 2WD
4%
4WD shift switch: AUTO 96 - 4%
4WD shift switch: 4H or
4LO 4%
2-4WD SOL [ON/OFF] Condition of 2-4WD shift
solenoid valve • Vehicle stopped
• Engine running
• A/T selector lever N posi-
tion
• Brake pedal depressed 4WD shift switch: 2WD
OFF
4WD shift switch: AUTO ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(Wait function is operat-
ing.) OFF
4WD shift switch: 4H
(Wait function is operat-
ing.) OFF
2-4WD SOL MON [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: 2WD
OFF
4WD shift switch: AUTO ON
4WD shift switch: 4H
4WD shift switch: 4LO
4WD shift switch: AUTO
(Wait function is operat-
ing.) OFF
4WD shift switch: 4H
(Wait function is operat-
ing.) OFF
MOTOR RELAY [ON/
OFF] Condition of transfer mo-
tor relay • Accelerator pedal de-
pressed
• Vehicle stopped
• Engine running
• Brake pedal depressed 4WD shift switch: 2WD
OFF
4WD shift switch: AUTO
or 4LO (A/T selector lever
P or N position) OFF
(ON for approx. 2 sec. after shifting to P and N.)
4WD shift switch: AUTO
or 4LO (Except for A/T se-
lector lever P or N posi-
tion) ON
4WD shift switch: 4H (A/T
selector lever P position) OFF
(ON fo r appro
x
. 2
sec. after shifting to P.)
4WD shift switch: 4H (Ex-
cept for A/T selector lever
P position) ON
Monitored item [Unit]
Content ConditionDisplay value
Revision: March 2010 2008 QX56

DLN-110
< SYMPTOM DIAGNOSIS >[ATX14B]
4WD WARNING LAMP FLASHES RAPIDLY
4WD WARNING LAMP FLASHES RAPIDLY
DescriptionINFOID:0000000001737193
The 4WD warning lamp flashes quickly while driving (2 times / second). The lamp continues to flash until the
ignition switch is turned OFF.
Diagnosis ProcedureINFOID:0000000001737194
1.CHECK TIRE
Check the following.
• Tire pressure
• Wear condition
• Longitudinal tire size (There is no difference between longitudinal tires.)
Are the inspection results normal?
YES >> GO TO 2.
NO >> Repair or replace damaged parts.
2.CHECK 4WD WARNING LAMP
Stop the vehicle and allow it to idle for a short period of time.
Does flashing stop?
YES >> Inspection End.
NO >> GO TO 3.
3.CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fluid temperature system. Refer to DLN-67, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 5.
5.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> Inspection End.
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.
Revision: March 2010 2008 QX56

4WD WARNING LAMP FLASHES SLOWLYDLN-111
< SYMPTOM DIAGNOSIS > [ATX14B]
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4WD WARNING LAMP FLASHES SLOWLY
DescriptionINFOID:0000000001737195
The 4WD warning lamp flashes slowly while driving (1 ti me / 2 seconds). The lamp continues to flash until the
ignition switch is turned OFF.
Diagnosis ProcedureINFOID:0000000001737196
1.CHECK TIRE
Check the following.
• Tire pressure
• Wear condition
• Longitudinal tire size (There is no difference between longitudinal tires.)
OK or NG
OK >> GO TO 2.
NG >> Repair or replace damaged parts.
2.CHECK TRANSFER FLUID TEMPERATURE
Perform trouble diagnosis for transfer fl uid temperature system. Refer to DLN-67, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 3.
NO >> Repair or replace damaged parts.
3.CHECK CLUTCH PRESSURE SWITCH
Perform trouble diagnosis for clutch pr essure switch system. Refer to DLN-70, "
Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 4.
NO >> Repair or replace damaged parts.
4.SYMPTOM CHECK
Check again.
Are the inspection results normal?
YES >> Inspection End.
NO >> GO TO 5.
5.CHECK TRANSFER CONTROL UNIT
Check transfer control unit input/output signal. Refer to DLN-80, "
Reference Value".
Are the inspection results normal?
YES >> Inspection End.
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.
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

EC-1
ENGINE
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SECTION EC
A
EC
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CONTENTS
ENGINE CONTROL SYSTEM
VK56DE
BASIC INSPECTION ....... .............................
8
DIAGNOSIS AND REPAIR WORKFLOW ..... .....8
Trouble Diagnosis Introduction ........................... ......8
INSPECTION AND ADJUSTMENT ....................13
Basic Inspection .................................................. ....13
Idle Speed and Ignition Timing Check ....................17
Procedure After Replacing ECM .............................17
VIN Registration ......................................................17
Accelerator Pedal Released Position Learning .......18
Throttle Valve Closed Position Learning .................18
Idle Air Volume Learning .........................................18
FUNCTION DIAGNOSIS ..............................21
ENGINE CONTROL SYSTEM ........................ ....21
System Diagram .................................................. ....21
Engine Control Component Parts Location .............22
MULTIPORT FUEL INJECTION SYSTEM ..... ....28
System Description ............................................. ....28
ELECTRIC IGNITION SYSTEM ..................... ....31
System Description ............................................. ....31
AIR CONDITIONING CUT CONTROL ...............32
Input/Output Signal Chart .................................... ....32
System Description .................................................32
AUTOMATIC SPEED CONTROL DEVICE
(ASCD) ...............................................................
33
System Description ............................................. ....33
Component Description ...........................................34
CAN COMMUNICATION ....................................35
System Description ............................................. ....35
COOLING FAN CONTROL ................................36
Description ..............................................................36
EVAPORATIVE EMISSION SYSTEM ...............37
Description ........................................................... ....37
INTAKE VALVE TIMING CONTROL ................40
Description ...............................................................40
ON BOARD DIAGNOSTIC (OBD) SYSTEM ....41
Introduction ..............................................................41
Two Trip Detection Logic .........................................41
Emission-related Diagnostic Information .................42
Malfunction Indicator Lamp (MIL) ............................55
OBD System Operation Chart .................................58
CONSULT-III Function (ENGINE) ...........................63
Generic Scan Tool (GST) Function .........................72
COMPONENT DIAGNOSIS .........................75
TROUBLE DIAGNOSIS - SPECIFICATION
VALUE ...............................................................
75
Description ........................................................... ....75
Testing Condition .....................................................75
Inspection Procedure ...............................................75
Diagnosis Procedure ...............................................76
POWER SUPPLY AND GROUND CIRCUIT ....83
Diagnosis Procedure ...............................................83
Ground Inspection ...................................................86
U1000, U1001 CAN COMM CIRCUIT ...............87
Description ...............................................................87
On Board Diagnosis Logic .......................................87
DTC Confirmation Procedure ..................................87
Diagnosis Procedure ...............................................87
U1010 CONTROL UNIT (CAN) .........................88
Description ...............................................................88
On Board Diagnosis Logic .......................................88
DTC Confirmation Procedure ..................................88
Diagnosis Procedure ...............................................88
P0011, P0021 IVT CONTROL ...........................90
On Board Diagnosis Logic .......................................90
Revision: March 2010 2008 QX56

EC-7
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DTC Index ...........................................................
..
462
Emission-related Diagnostic Information ...............466
SYMPTOM DIAGNOSIS ..... .......................481
ENGINE CONTROL SYSTEM SYMPTOMS .. ..481
Symptom Matrix Chart ........................................ ..481
NORMAL OPERATING CONDITION ...............485
Fuel Cut Control (at No Load and High Engine
Speed) ................................................................. ..
485
PRECAUTION ............................................486
PRECAUTIONS .............................................. ..486
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ..
486
Precaution Necessary for Steering Wheel Rota-
tion After Battery Disconnect ............................... ..
486
On Board Diagnosis (OBD) System of Engine and
A/T .........................................................................
487
Precaution .............................................................487
PREPARATION .........................................491
PREPARATION .............................................. ..491
Special Service Tool ........................................... ..491
Commercial Service Tool ......................................492
ON-VEHICLE MAINTENANCE ..................494
FUEL PRESSURE .......................................... ..494
Fuel Pressure Check .............................................494
EVAP LEAK CHECK ......................................496
How to Detect Fuel Vapor Leakage ..................... ..496
ON-VEHICLE REPAIR ...............................498
EVAP CANISTER ............................................498
Component Inspection ......................................... ..498
Removal and Installation .......................................498
INTAKE VALVE TIMING CONTROL ..............500
Intake Valve Timing Control Solenoid Valve (LH) ..500
Intake Valve Timing Cont rol Solenoid Valve (RH) ..500
Intake Valve Timing Control Position Sensor (LH) ..501
Intake Valve Timing Control Position Sensor (RH) ..501
Camshaft Position Sensor (PHASE) .....................501
SERVICE DATA AND SPECIFICATIONS
(SDS) ............... .......................................... .
503
SERVICE DATA AND SPECIFICATIONS
(SDS) ...............................................................
503
Fuel Pressure ...................................................... ..503
Idle Speed and Ignition Timing ..............................503
Calculated Load Value ..........................................503
Mass Air Flow Sensor ............................................503
Intake Air Temperature Sensor .............................503
Engine Coolant Temperature Sensor ....................503
A/F Sensor 1 Heater ..............................................503
Heated Oxygen sensor 2 Heater ...........................504
Crankshaft Position Sensor (POS) ........................504
Camshaft Position Sensor (PHASE) .....................504
Throttle Control Motor ............................................504
Fuel Injector ...........................................................504
Fuel Pump .............................................................504
Revision: March 2010 2008 QX56

EC-8
< BASIC INSPECTION >[VK56DE]
DIAGNOSIS AND REPAIR WORKFLOW
BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
Trouble Diagnosis IntroductionINFOID:0000000001351337
INTRODUCTION
The engine has an ECM to control major systems such as fuel con-
trol, ignition control, idle air control system, etc. The ECM accepts
input signals from sensors and instantly drives actuators. It is essen-
tial that both input and output signals are proper and stable. At the
same time, it is important that there are no malfunctions such as vac-
uum leaks, fouled spark plugs, or
other malfunctions with the engine.
It is much more difficult to diagnose an incident that occurs intermit-
tently rather than continuously. Most intermittent incidents are
caused by poor electric connections or improper wiring. In this case,
careful checking of suspected circuits may help prevent the replace-
ment of good parts.
A visual check only may not find the cause of the incidents. A road
test with CONSULT-III (or GST) or a circuit tester connected should
be performed. Follow the Work Flow on "WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a
customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such incidents, especially
intermittent ones. Find out what symptoms are present and under
what conditions they occur. A Di agnostic Worksheet like the example
on "Worksheet Sample" should be used.
Start your diagnosis by looking fo r conventional malfunctions first.
This will help troubleshoot driveability malfunctions on an electroni-
cally controlled engine vehicle.
WORK FLOW
MEF036D
SEF233G
SEF234G
Revision: March 2010 2008 QX56