2008 INFINITI QX56 service

HAC-2
MAGNET CLUTCH ............................................71
System Description .............................................. ...71
Magnet Clutch Component Function Check ........ ...71
Magnet Clutch Diagnosis Procedure ................... ...72
WATER VALVE CIRCUIT ..................................76
Description ........................................................... ...76
Water Valve Diagnosis Procedure ..........................76
AMBIENT SENSOR ...........................................78
Component Description ....................................... ...78
Ambient Sensor Diagnosis Procedure ....................78
Ambient Sensor Component Inspection .................79
IN-VEHICLE SENSOR .......................................81
Component Description ....................................... ...81
In-Vehicle Sensor Diagnosis Procedure .................81
In-Vehicle Sensor Component Inspection ..............83
OPTICAL SENSOR ...........................................84
Component Description ..........................................84
Optical Sensor Diagnosis Procedure ......................84
INTAKE SENSOR ..............................................86
System Description .............................................. ...86
Intake Sensor Diagnosis Procedure .......................86
Intake Sensor Component Inspection ................. ...87
POWER SUPPLY AND GROUND CIRCUIT
FOR CONTROLLER ..........................................
88
Component Description ....................................... ...88
A/C Auto Amp. Component Function Check ..........88
A/C Auto Amp Power and Ground Diagnosis Pro-
cedure .....................................................................
89
ECU DIAGNOSIS .......................................90
AIR CONDITIONER CONTROL ..................... ...90
A/C Auto Amp. Terminals Reference Values ..........90
Wiring Diagram .................................................... ...92
SYMPTOM DIAGNOSIS ...........................108
AIR CONDITIONER CONTROL ..................... ..108
Symptom Matrix Chart ........................................ .108
INSUFFICIENT COOLING ................................109
Component Function Check ................................ .109
Diagnostic Work Flow ...........................................110
Performance Chart ................................................113
Trouble Diagnoses for Abnormal Pressure ...........114
INSUFFICIENT HEATING ................................117
Component Function Check .................................117
NOISE ...............................................................119
Component Function Check ................................ .119
MEMORY FUNCTION DOES NOT OPERATE ..121
Memory Function Check ...................................... .121
PRECAUTION ...........................................122
PRECAUTIONS .............................................. ..122
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .............................................................. .
122
Working with HFC-134a (R-134a) ........................ .122
Precaution for Service Equipment ........................123
Revision: March 2010 2008 QX56

DIAGNOSIS AND REPAIR WORKFLOWHAC-3
< BASIC INSPECTION > [AUTOMATIC AIR CONDITIONER]
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BASIC INSPECTION
DIAGNOSIS AND REPAIR WORKFLOW
How to Perform Trouble Diagnosis For Quick And Accurate RepairINFOID:0000000001679763
WORK FLOW
1.LISTEN TO CUSTOMER COMPLAINT
Listen to customer complaint. Get detailed information about the conditions and environment when the symp-
tom occurs.
>> GO TO 2
2.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 3.
3.VERIFY THE SYMPTOM WITH OPERATIONAL CHECK
Verify the symptom with operational check. Refer to HAC-4, "
Operational Check (Front)".
Can a symptom be duplicated?
YES >> GO TO 4
NO >> GO TO 5
4.GO TO APPROPRIATE TROUBLE DIAGNOSIS
Go to appropriate trouble diagnosis. Refer to HAC-108, "
SymptomMatrixChart".
Can a symptom be duplicated?
>> GO TO 5.
5.PERFORM THE A/C AUTO AMP SELF-DIAGNOSIS
Perform A/C auto amp. self-diagnosis. Refer to HAC-22, "
A/C Auto Amp. Self-Diagnosis".
>> If any diagnostic trouble codes set. Refer to HAC-23, "
A/C System Self-Diagnosis Code Chart".
>> Confirm the repair by perform ing operational check. Refer to HAC-4, "
Operational Check (Front)".
Revision: March 2010 2008 QX56

MODE DOOR MOTORHAC-25
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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The mode door motor (front) is attached to the heater & cooling unit
assembly. It rotates so that air is discharged from the outlet as indi-
cated by the A/C auto amp. Motor rotation is conveyed to a link
which activates the mode door.
Mode Door Motor (Front) Component Function CheckINFOID:0000000001679783
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING O PERATIONAL CHECK - DISCHARGE AIR
1. Press mode switch four times and then press the (DEF) switch. Each position indicator should change shape (on display).
2. Confirm that discharge air comes out accordi ng to the air distribution table. Refer to HAC-15, "
Discharge
Air Flow (Front)".
NOTE:
Confirm that the compressor clutch is engaged (visual inspection) and intake door position is at FRESH
when DEF ( ) or D/F ( ) is selected.
Can a symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to HAC-4, "
Operational Check
(Front)".
Can a symptom be duplicated?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK MODE DOOR OPERATION
Check and verify mode door mechanism for smooth operation in each mode.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair as necessary.
5.PERFORM A/C AUTO AMP. SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-22, "
A/C Auto Amp. Self-Diagnosis".
Are any self-diagnosis codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 6.
6.PERFORM A/C AND AV SWITCH ASSEMBLY SELF-DIAGNOSIS
Perform self-diagnosis to check the A/C and AV switch assembly. Refer to HAC-22, "
A/C and AV Switch
Assembly Self-Diagnosis".
Is the inspection result normal?
YES >> Replace A/C and AV switch assembly. Refer to VTL-7, "Removal and Installation".
NO >> GO TO 7.
WJIA0587E
Revision: March 2010 2008 QX56

HAC-32
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AIR MIX DOOR MOTOR
Perform a complete operational check and check for any symptoms. Refer to
HAC-4, "Operational Check
(Front)".
Can a symptom be duplicated?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> System OK.
4.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 5.
5.CHECK AIR MIX DOOR OPERATION
Check and verify air mix door mechanism for smooth operation from 18 °C (60° F) to 32° C (90°F) in each
mode.
Is the inspection result normal?
YES >> GO TO 6.
NO >> Repair as necessary.
6.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-22, "
A/C and AV Switch Assembly Self-Diagno-
sis".
Are any self-diagnosis codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 7.
7.CHECK THE AIR MIX DOOR MOTOR PBR CIRCUIT
Perform diagnostic procedure for the air mix door motors. Refer to HAC-31, "
Air Mix Door Motor Component
Function Check".
Is the inspection result normal?
YES >> GO TO 8.
NO >> Repair PBR circuit or replace air mix door motor. Refer to VTL-26, "
Removal and Installation".
8.RECHECK FOR CODES
Perform self-diagnosis. Refer to HAC-22, "
A/C and AV Switch Assembly Self-Diagnosis".
Are any self-diagnostic codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 9.
9.RECHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-4, "
Operational Check (Front)".
Does another symptom exist?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
Air Mix Door Motor (Driver) Diagnosis ProcedureINFOID:0000000001679787
SYMPTOM:• Discharge air temperature does not change.
• Air mix door motor does not operate.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (DRIVER)
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
Revision: March 2010 2008 QX56

INTAKE DOOR MOTORHAC-41
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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COMPONENT DESCRIPTION
Intake door motor
The intake door motor is attached to the intake unit. It rotates so that
air is drawn from inlets set by the A/C auto amp. Motor rotation is
conveyed to a lever which activates the intake door.
Intake Door Motor Component Function CheckINFOID:0000000001679790
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - REC ( )
1. Press the mode switch to vent mode( ).
2. Press REC ( ) switch. The REC ( )indicator should illuminate.
3. Press REC ( ) switch again. The REC ( ) indicator should go out.
4. Listen for intake door position change (you should hear blower sound change slightly).
Can a symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to HAC-4, "
Operational Check
(Front)".
Can a symptom be duplicated?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK INTAKE DOOR OPERATION
Check and verify intake door me chanism for smooth operation.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair intake door mechanism.
5.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-22, "
A/C and AV Switch Assembly Self-Diagno-
sis".
Are any self-diagnosis codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 6.
6.RECHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-4, "
Operational Check (Front)".
Does another symptom exist?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
WJIA0552E
Revision: March 2010 2008 QX56

DEFROSTER DOOR MOTOR CIRCUITHAC-45
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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Defroster Door Motor Co mponent Function CheckINFOID:0000000001679793
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING O PERATIONAL CHECK - DEFROSTER DOOR
1. Press the mode switch and select vent ( ).
2. Press the defrost switch ( ). Defroster indicator should illuminate (on display).
3. Listen for defroster door position change (blower sound should change slightly).
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-4, "
Operational Check (Front)".
Does another symptom exist?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> SYSTEM OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK DEFROSTER DOOR MOTOR
Perform diagnostic procedure for defroster door motor. Refer to HAC-45, "
Defroster Door Motor Component
Function Check".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair PBR circuit or replace defroster door motor. Refer to VTL-21, "
Removal and Installation".
5.CHECK DEFROSTER DOOR OPERATION
Check and verify defroster door mechanism for smooth operation.
Is the inspection result normal?
YES >> Replace defroster door motor. Refer to VTL-21, "Removal and Installation".
NO >> Repair defroster door mechanism.
Defroster Door Motor Diagnosis ProcedureINFOID:0000000001679794
SYMPTOM:
• Defroster door does not change.
• Defroster door motor does not operate normally.
DIAGNOSTIC PROCEDURE FOR DEFROSTER DOOR MOTOR
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the defroster switch ( ).
3. Check voltage between A/C auto amp. harness connector M49 terminal 24 and terminal 23 and press the defroster switch ( )
again.
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 24 23 Press de-
froster switch Battery
voltage
AWIIA0152ZZ
Revision: March 2010 2008 QX56

HAC-50
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
BLOWER MOTOR CONTROL SYSTEM
Blower Speed Compensation - Sunload
When the in-vehicle temperature and the set temperature
are very close, the blower will be operating at low
speed. The speed will vary depending on the sunload. During conditions of low or no sunload, the blower
operates at low speed. During high sunload conditions, the A/C auto amp. causes the blower speed to
increase.
Blower Speed Control Specification
COMPONENT DESCRIPTION
Variable Blower Control
The variable blower control is located on the cooling unit. The vari-
able blower control receives a gate voltage from the A/C auto amp.
to steplessly maintain the blower motor voltage in the 0 to 5 volt
range (approx.).
Front Blower Motor Co mponent Function CheckINFOID:0000000001679796
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - FRONT BLOWER
1. Push blower motor (+) switch. Blower motor should operate.
2. Push blower motor (+) switch, and continue checki ng blower speed and fan symbol until all speeds are
checked.
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-4, "
Operational Check (Front)".
Does another symptom exist?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.PERFORM A/C AUTO AMP. SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-22, "
A/C Auto Amp. Self-Diagnosis".
Are any self-diagnosis codes present?
WJIA0441E
WJIA0559E
Revision: March 2010 2008 QX56

HAC-56
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
BLOWER MOTOR CONTROL SYSTEM
System Operation
Rear Blower Control
When the rear blower control dial (front) REAR CTRL switch is pressed (indicator on), it allows the rear air
control (rear) to control the rear blower motor speed. If t
he REAR CTRL switch is off (indicator off), the rear air
control (front) controls the rear blower motor s peed regardless of the rear air control (rear) position.
Rear Blower Motor Component Function CheckINFOID:0000000001679800
INSPECTION FLOW
SYMPTOM:
• Rear blower motor does not operate from the rear air control (front) and the rear air control (rear).
• Rear blower motor operates from rear air control (front) only.
• Rear blower motor operates in high at all times.
INSPECTION FLOW
1.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 2.
2.CONFIRM SYMPTOM BY PERFORMING REAR BLOW ER MOTOR OPERATIONAL CHECK FROM REAR
AIR CONTROL (FRONT)
1. Turn ignition switch ON.
2. Turn the rear air control (front) blower control dial to the lowest speed and check for rear blower operation
(REAR CTRL indicator off).
3. Continue checking that rear blower speed increases as the rear blower control dial is rotated clockwise.
Does the rear blower motor operate correctly?
YES >> GO TO 3.
NO >> Check the rear blower motor operation. Refer to HAC-56, "
Rear Blower Motor Component Func-
tion Check".
3.CONFIRM SYMPTOM BY PERFORMING REAR BLOWER MOTOR OPERATIONAL CHECK FROM
REAR AIR CONTROL (REAR)
1. Press the REAR CTRL switch (indicator on) on the rear air control (front) to send control of the rear blower
motor back the rear air control (rear).
2. Turn the rear air control (rear) blower control dial to the lowest speed and check for rear blower operation.
3. Continue checking that rear blower speed increases as the rear blower control dial is rotated clockwise.
Does the rear blower motor operate correctly?
YES >> GO TO 4.
AWIIA0181GB
Revision: March 2010 2008 QX56