2010 INFINITI QX56 diagram

HAC-1
VENTILATION, HEATER & AIR CONDITIONER
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CONTENTS
HEATER & AIR CONDITIONING CONTROL SYSTEM
AUTOMATIC AIR CONDITIONER
BASIC INSPECTION ....... .............................
3
DIAGNOSIS AND REPAIR WORKFLOW ..... .....3
How to Perform Trouble Diagnosis For Quick And
Accurate Repair ........................................................
3
INSPECTION AND ADJUSTMENT ................ .....4
Operational Check (Front) ................................... ......4
Operational Check (Rear) .........................................5
FUNCTION DIAGNOSIS ...............................7
FUNCTION INFORMATION ........................... .....7
Component Part Location ................................... ......7
Symptom Table .........................................................9
REFRIGERATION SYSTEM ..............................11
Refrigerant Cycle ................................................ ....11
Refrigerant System Protection ................................11
AUTOMATIC AIR CONDITIONER SYSTEM . ....13
Control System Diagram ..................................... ....13
Control System Description .....................................13
Discharge Air Flow (Front) ......................................16
Discharge Air Flow (Rear) .......................................16
Switches And Their Control Function (Front) ..........18
Switches And Their Control Function (Rear) ...........19
DIAGNOSIS SYSTEM (HVAC) ..........................20
CONSULT-III Function (HVAC) ........................... ....20
DIAGNOSIS SYSTEM (BCM) ............................21
CONSULT-III Function (BCM - COMMON ITEM) ....21
CONSULT-III Function (BCM - AIR CONDITION-
ER) ...................................................................... ....
21
SELF-DIAGNOSIS FUNCTION ..........................23
A/C Auto Amp. Self-Diagnosis ................................23
A/C and AV Switch Asse mbly Self-Diagnosis .........23
A/C System Self-Diagnosis Code Chart .............. ....24
COMPONENT DIAGNOSIS .........................25
MODE DOOR MOTOR ......................................25
System Description .............................................. ....25
Mode Door Motor (Front) Component Function
Check ......................................................................
26
Mode Door Motor (Front) Diagnosis Procedure ......26
AIR MIX DOOR MOTOR ...................................30
System Description ..................................................30
Air Mix Door Motor (Driver) Component Function
Check ......................................................................
31
Air Mix Door Motor (Driver) Diagnosis Procedure ....32
Air Mix Door Motor (Passenger) Component
Function Check ........................................................
35
Air Mix Door Motor (Passenger) Diagnosis Proce-
dure .........................................................................
35
INTAKE DOOR MOTOR ...................................39
System Description ..................................................39
Intake Door Motor Component Function Check ......40
Intake Door Motor Diagnosis Procedure .................40
DEFROSTER DOOR MOTOR CIRCUIT ...........42
System Description ..................................................42
Defroster Door Motor Component Function Check
....
43
Defroster Door Motor Diagnosis Procedure ............43
BLOWER MOTOR CONTROL SYSTEM ..........47
System Description ..................................................47
Front Blower Motor Component Function Check ....48
Front Blower Motor Diagnosis Procedure ................48
Front Blower Motor Component Inspection .............52
Rear Blower Motor Description ................................53
Rear Blower Motor Component Function Check .....53
Rear Air Control (Front) Diagnosis Procedure #1 ....54
Rear Air Control (Rear) Diagnosis Procedure #2 ....56
Rear Blower Motor Component Inspection ..............57
REAR AIR CONTROL SYSTEM .......................58
Rear Air Control System Description .......................58
Revision: April 20092010 QX56

HAC-2
Rear Air Control Component Function Check ........58
Air Mix Door Motor (Rear) Diagnosis Procedure ....59
Mode Door Motor (Rear) Diagnosis Procedure ......63
MAGNET CLUTCH ............................................68
System Description .............................................. ...68
Magnet Clutch Component Function Check ........ ...68
Magnet Clutch Diagnosis Procedure ................... ...68
WATER VALVE CIRCUIT ..................................73
Description ........................................................... ...73
Water Valve Diagnosis Procedure ..........................73
AMBIENT SENSOR ...........................................75
Component Description ....................................... ...75
Ambient Sensor Diagnosis Procedure ....................75
Ambient Sensor Component Inspection .................76
IN-VEHICLE SENSOR .......................................78
Component Description ....................................... ...78
In-Vehicle Sensor Diagnosis Procedure .................78
In-Vehicle Sensor Component Inspection ..............80
OPTICAL SENSOR ...........................................81
Component Description ..........................................81
Optical Sensor Diagnosis Procedure ......................81
INTAKE SENSOR ..............................................83
System Description .............................................. ...83
Intake Sensor Diagnosis Procedure .......................83
Intake Sensor Component Inspection ................. ...84
POWER SUPPLY AND GROUND CIRCUIT
FOR CONTROLLER ..........................................
86
Component Description ....................................... ...86
A/C Auto Amp. Component Function Check ..........86
A/C Auto Amp Power and Ground Diagnosis Pro-
cedure .................................................................. ...
87
ECU DIAGNOSIS .......................................89
AIR CONDITIONER CONTROL ..................... ...89
A/C Auto Amp. Terminals Reference Values ..........89
Wiring Diagram .................................................... ...91
SYMPTOM DIAGNOSIS ...........................107
AIR CONDITIONER CONTROL ..................... ..107
Symptom Matrix Chart ........................................ .107
INSUFFICIENT COOLING ................................108
Component Function Check ................................ .108
Diagnostic Work Flow ...........................................109
Performance Chart ................................................111
Trouble Diagnoses for Abnormal Pressure ...........112
INSUFFICIENT HEATING ................................116
Component Function Check .................................116
NOISE ...............................................................118
Component Function Check ................................ .118
MEMORY FUNCTION DOES NOT OPERATE ..120
Memory Function Check ...................................... .120
PRECAUTION ...........................................121
PRECAUTIONS .............................................. ..121
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" .............................................................. .
121
Working with HFC-134a (R-134a) ........................ .121
Precaution for Service Equipment ........................122
Revision: April 20092010 QX56

AUTOMATIC AIR CONDITIONER SYSTEMHAC-13
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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AUTOMATIC AIR CONDITIONER SYSTEM
Control System DiagramINFOID:0000000005147675
CONTROL SYSTEM
The control system consists of input sensors, switches, the A/C auto amp.(microcomputer) and outputs.
The relationship of these components is shown in the figure below:
Control System DescriptionINFOID:0000000005147676
CONTROL OPERATION
AWIIA0088GB
Revision: April 20092010 QX56

HAC-26
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
MODE DOOR MOTOR
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:0000000005147688
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OP ERATIONAL 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 according to the air distribution table. Refer to HAC-16, "
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.
Is the inspection result normal?
YES >> Inspection End.
NO >> Go to diagnosis procedure. Refer to HAC-26, "
Mode Door Motor (Front) Diagnosis Procedure".
Mode Door Motor (Front) Diagnosis ProcedureINFOID:0000000005147689
Regarding Wiring Diagram information, refer to HAC-91, "Wiring Diagram".
SYMPTOM:• Air outlet does not change.
• Mode door motor does not operate normally.
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the mode switch to the B/L ( ) mode.
3. Check voltage between A/C auto amp. harness connector M49 terminal 19 and terminal 20 while pressing the mode switch to
the floor ( ) mode.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK MODE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
WJIA0587E
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 20
19Press
mode
switch Battery
voltage
AWIIA0095ZZ
Revision: April 20092010 QX56

HAC-32
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AIR MIX DOOR MOTOR
Air Mix Door Motor (Driver) Diagnosis Procedure
INFOID:0000000005147692
Regarding Wiring Diagram information, refer to HAC-91, "Wiring Diagram".
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
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32 °C (90° F).
3. Check voltage between A/C auto amp. harness connector M49
terminal 17 and terminal 18 while rotating temperature control
dial (driver) to 18 °C (60° F).
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK AIR MIX DOOR MOTOR (DRIVE R) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 17, 18 and ground.
Is the inspection result normal?
YES >> Replace A/C auto amp. Refer to VTL-7, "Removal and
Installation".
NO >> Repair or replace harness as necessary.
3.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32 °C (90° F).
3. Check voltage between A/C auto amp. harness connector M49 terminal 17 and terminal 18 while rotating temperature control
dial (driver) to 18 °C (60° F).
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 17 18
Rotate temp
control dial Battery
voltage
AWIIA0112ZZ
17 - Ground : Continuity should not exist.
18 - Ground : Continuity should not exist.
AWIIA0114ZZ
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 18 17 Rotate temp
control dial Battery
voltage
AWIIA0115ZZ
Revision: April 20092010 QX56

AIR MIX DOOR MOTORHAC-35
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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1. Turn ignition switch OFF.
2. Disconnect the air mix door motor (driver) harness connector and A/C auto amp. harness connector.
3. Check continuity between air mix door motor (driver) harness connector M147 (B) terminal 4 and A/C auto amp. harness con-
nector M49 (A) terminal 6.
Is the inspection result normal?
YES >> Replace air mix door motor (driver). Refer to VTL-31,
"Removal and Installation".
NO >> Repair or replace harness as necessary.
Air Mix Door Motor (Passen ger) Component Function CheckINFOID:0000000005272349
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERAT IONAL CHECK - TEMPERATURE INCREASE
1. Turn the temperature control dial (passenger) clockwise until 32 °C (90 °F) is displayed.
2. Check for hot air at discharge air outlets.
>> GO TO 2.
2.CONFIRM SYMPTOM BY PERFORMING OPERAT IONAL CHECK - TEMPERATURE DECREASE
1. Turn the temperature control dial (passenger) counterclockwise until 18° C (60°F) is displayed.
2. Check for cold air at discharge air outlets.
Is the inspection result normal?
YES >> Inspection End.
NO >> Go to diagnosis procedure. Refer to HAC-35, "
Air Mix Door Motor (Passenger) Diagnosis Proce-
dure".
Air Mix Door Motor (Passe nger) Diagnosis ProcedureINFOID:0000000005147693
Regarding Wiring Diagram information, refer to HAC-91, "Wiring Diagram".
SYMPTOM:
• Discharge air temperature does not change.
• Air mix door motor does not operate.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (PASSENGER)
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 32 °C (90 °F).
3. Check voltage between A/C auto amp. harness connector M49
terminal 14 and terminal 2 while rotating temperature control dial
(passenger) to 18 ° C (60 °F).
Is the inspection result normal?
OK >> GO TO 3. Continuity should exist.
AWIIA0124ZZ
Connector
Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 2 14 Rotate temp
control dial Battery
voltage
AWIIA0125ZZ
Revision: April 20092010 QX56

HAC-40
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
INTAKE DOOR MOTOR
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:0000000005147695
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).
Is the inspection result normal?
YES >> Inspection End.
NO >> Go to diagnosis procedure. Refer to HAC-40, "
Intake Door Motor Diagnosis Procedure".
Intake Door Motor Diagnosis ProcedureINFOID:0000000005147696
Regarding Wiring Diagram information, refer to HAC-91, "Wiring Diagram".
SYMPTOM:
• Intake door does not change.
• Intake door motor does not operate normally.
DIAGNOSTIC PROCEDURE FOR INTAKE DOOR MOTOR
1.CHECK A/C AUTO AMP. FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Check voltage between A/C auto amp. harness connector M49 terminal 21 and terminal 22 while placing the HVAC system into
self-diagnostic mode.
Is the inspection result normal?
OK >> GO TO 3.
NO >> GO TO 2.
2.CHECK INTAKE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
WJIA0552E
Connector Te r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
A/C auto amp.: M49 21
22Self-diagnostic
mode Battery volt-
age
AWIIA0146ZZ
Revision: April 20092010 QX56

DEFROSTER DOOR MOTOR CIRCUITHAC-43
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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Defroster Door Motor Co mponent Function CheckINFOID:0000000005147698
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).
Is the inspection result normal?
YES >> Inspection End.
NO >> Go to diagnosis procedure. Refer to HAC-43, "
Defroster Door Motor Diagnosis Procedure".
Defroster Door Motor Diagnosis ProcedureINFOID:0000000005147699
Regarding Wiring Diagram information, refer to HAC-91, "Wiring Diagram".
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.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK DEFROSTER DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the A/C auto amp. harness connector.
3. Check continuity between A/C auto amp. harness connector M49 terminal 23, 24 and ground.
Is the inspection result normal?
YES >> Replace A/C auto amp. Refer to VTL-7, "Removal and
Installation".
NO >> Repair or replace harness as necessary.
3.CHECK A/C AUTO AMP. FOR GROUND AND POWER
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
23 - Ground : Continuity should not exist.
24 - Ground : Continuity should not exist.
AWIIA0153ZZ
Revision: April 20092010 QX56