Page 2322 of 4210
HA-30
< ON-VEHICLE REPAIR >
REFRIGERATION SYSTEM
Rear A/C System
NOTE:
Refer to HA-5, "
Precaution for Refrigerant Connection".
1. High-pressure service valve 2. Grommet 3. High-pressure pipe
4. Refrigerant pressure sensor 5. Condenser 6. Compressor shaft seal
7. High-pressure flexible hose 8. Low-pressure flexible hose 9. Low-pressure service valve
10. Low-pressure pipe 11. Expansion valve (front)12. Drain hose
AWIIA0134GB
1. Rear heater and cooling unit assembly 2. Rear A/C pipes 3. Rear A/C heater core pipes
4. Rear heater core hose 5. Rear blower motor6. Underfloor rear A/C pipes
7. Underfloor rear heater core pipes A. Bolt torque specification B. Leak checking order (l - r)
C. Tightening torque D. Wrench sizeE. O-ring size
Front
NOTE: The O-ring size 8 is the high-side and the O-ring size 16 is the low-side.
Revision: April 20092010 QX56
Page 2336 of 4210

HA-44
< ON-VEHICLE REPAIR >
CONDENSER
CONDENSER
Removal and Installation for CondenserINFOID:0000000005147663
REMOVAL
1. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Remove the radiator. Refer to CO-15, "
Removal and Installation".
CAUTION:
Be careful not to damage the core su rface of the condenser and the radiator.
3. Disconnect the high-pressure flexible hose and the high-pressure pipe from the condenser. CAUTION:
Cap or wrap the joint of the pipe with suitable ma terial such as vinyl tape to avoid the entry of air.
4. Disconnect the refrigerant pressure sensor connector. • Remove the refrigerant pressure sensor from the condenseras necessary.
5. Lift the condenser out of the mounting grommets to remove the condenser.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "
Component".
CAUTION:
• Replace the O-rings of the high-pressure pipe, refrigerant pressure sensor, and high-pressure flexi- ble hose with new ones, then apply compr essor oil to them when installing them.
• After charging refrigerant, check for leaks.
• Replace the grommets as necessary.
LJIA0145E
Revision: April 20092010 QX56
Page 2337 of 4210
AMBIENT SENSORHA-45
< ON-VEHICLE REPAIR >
C
DE
F
G H
J
K L
M A
B
HA
N
O P
AMBIENT SENSOR
Removal and InstallationINFOID:0000000005147664
REMOVAL
1. Disconnect the ambient sensor electrical connector. NOTE:
The ambient sensor (1) is located behind the front bumper, in
front of the condenser.
2. Release the ambient sensor clip and then remove the ambient sensor (1).
INSTALLATION
Installation is in the reverse order of removal.
AWIIA0238ZZ
Revision: April 20092010 QX56
Page 2338 of 4210
HA-46
< ON-VEHICLE REPAIR >
REFRIGERANT PRESSURE SENSOR
REFRIGERANT PRESSURE SENSOR
Removal and Installation for Refrigerant Pressure SensorINFOID:0000000005147665
REMOVAL
1. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Disconnect the refrigerant pressure sensor electrical connector and remove the refrigerant pressure sensor from the condenser.
CAUTION:
Be careful not to damage the condenser fins.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "
Component".
CAUTION:
• Be careful not to damage the condenser fins.
• Replace the O-ring of the refriger ant pressure sensor with a new one, then apply compressor oil to it
when installing it.
• After charging refrigerant, check for leaks.
LJIA0145E
Revision: April 20092010 QX56
Page 2342 of 4210

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
Page 2347 of 4210
FUNCTION INFORMATIONHAC-7
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
C
D
E
F
G H
J
K L
M A
B
HAC
N
O P
FUNCTION DIAGNOSIS
FUNCTION INFORMATION
Component Part LocationINFOID:0000000005147671
ENGINE COMPARTMENT
AWIIA1132GB
1. Water valve F68 2. Refrigerant pressure sensor E48 3. Ambient sensor E1
4. A/C compressor F3
Revision: April 20092010 QX56
Page 2348 of 4210
HAC-8
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
FUNCTION INFORMATION
PASSENGER COMPARTMENT
1. A/C auto amp. M49, M50
2. In-vehicle sensor M323. Intake sensor M146
4. Intake door motor M58 5. Variable blower control (front)
M122 6. Air mix door motor (passenger) M143
7. Mode door motor (front) M142 8. Defroster door motor M144 9. Air mix door motor (driver) M147
10. Optical sensor M302 ⇐:Front
AWIIA0567ZZ
Revision: April 20092010 QX56
Page 2351 of 4210
![INFINITI QX56 2010 Factory Service Manual REFRIGERATION SYSTEMHAC-11
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
C
D
E
F
G H
J
K L
M A
B
HAC
N
O P
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000005197357
REFRIGERANT FLOW
The refri INFINITI QX56 2010 Factory Service Manual REFRIGERATION SYSTEMHAC-11
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
C
D
E
F
G H
J
K L
M A
B
HAC
N
O P
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000005197357
REFRIGERANT FLOW
The refri](/manual-img/42/57032/w960_57032-2350.png)
REFRIGERATION SYSTEMHAC-11
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
C
D
E
F
G H
J
K L
M A
B
HAC
N
O P
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000005197357
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the front and rear evaporators, and back to the compressor. The refrigerant evaporation through the
evaporator coils are controlled by front and rear externally equalized expansion valves, located inside the front
and rear evaporator cases.
Refrigerant System ProtectionINFOID:0000000005197358
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively hi gh or low pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM.
The ECM de-energizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressu re sensor is over about 2,746 kPa (28 kg/cm
2, 398 psi), or below
about 120 kPa (1.22 kg/cm
2, 17.4 psi).
WJIA1342E
Revision: April 20092010 QX56