INFINITI QX56 2010 Factory Service Manual

REFRIGERATION SYSTEMHAC-11
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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
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HAC-12
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REFRIGERATION SYSTEM
PRESSURE RELIEF VALVE
The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.
When the pressure of refrigerant in the system increases to an abnormal level [more than 2,990 kPa (30.5 kg/
cm
2, 433.6 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into
the atmosphere.
Revision: April 20092010 QX56

AUTOMATIC AIR CONDITIONER SYSTEMHAC-13
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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
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HAC-14
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AUTOMATIC AIR CONDITIONER SYSTEM
A/C auto amp.
DISPLAY SCREEN
Displays the operational status of the system.
AUTO SWITCH
• The compressor, intake door, air mix doors, outlet
doors and blower speed are automatically controlled so
that the in-vehicle temperature will reach, and be mainta ined at the set temperature selected by the operator.
• When pressing AUTO switch, air inlet, air outlet, bl ower speed, and discharge air temperature are automati-
cally controlled.
TEMPERATURE CONTROL DIAL (DRIVER)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (PASSENGER)
Increases or decreases the set temperature.
RECIRCULATION ( ) SWITCH
• When REC switch is ON, REC switch indicator turns ON, and air inlet is set to REC.
• When REC switch is turned OFF, or when compressor is turned from ON to OFF, REC switch is automati-
cally turned OFF. REC mode can be re-entered by pressing REC switch again.
• REC switch is not operated when DEF switch is tur ned ON, at the D/F position, or in floor position.
DEFROSTER ( ) SWITCH
Positions the air outlet doors to the defrost position. Al so positions the intake doors to the outside air position,
and turns A/C compressor ON.
REAR WINDOW DEFOGGER SWITCH
When switch is ON, rear window and door mirrors are defogged.
OFF SWITCH
The compressor and blower are OFF, the intake doors are set to the outside air position, and the air outlet
doors are set to the foot (75% foot and 25% defrost) position.
A/C SWITCH
The compressor is ON or OFF.
(Pressing the A/C switch when the AUTO switch is ON will turn off the A/C switch and compressor.)
MODE SWITCH
Controls the air discharge outlets.
FRONT BLOWER CONTROL SWITCHES
Manually control the blower speed.
AWIIA0081ZZ
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AUTOMATIC AIR CONDITIONER SYSTEMHAC-15
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Rear Air Controls
REAR TEMPERATURE CONTROL DIAL (FRONT/REAR)
The temperature increases or dec reases the set temperature.
REAR MODE SWITCHES (FRONT/REAR)
Controls the air discharge outlets.
REAR BLOWER CONTROL DIAL (FRONT)
When the REAR CTRL switch is in the off (indicator off) the rear air control (front) controls the rear blower
motor speed regardless of the rear air control (rear) blow er control dial (rear) position. The rear air control
(front) controls the blower motor speed.
REAR BLOWER CONTROL DIAL (REAR)
When the REAR CTRL switch is in the on (indicator on) the rear air control (rear) controls the rear blower
motor speed regardless of the rear air control (front) blow er control dial (front) position. The rear air control
(rear) controls the blower motor speed.
MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, A/ C auto amp. inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM and A/C auto amp., via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sen-
sor signal, throttle angle sensor, etc.). If it judges compressor can be turned ON, it sends compressor ON sig-
nal to IPDM E/R, via CAN communication line.
AWIIA0082ZZ
1. Rear air control (front )2. Rear air control (rear)
AWIIA1069GB
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HAC-16
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AUTOMATIC AIR CONDITIONER SYSTEM
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
Discharge Air Flow (Front)INFOID:0000000005147677
Discharge Air Flow (Rear)INFOID:0000000005147678

Mode door positionAir outlet/distribution
Vent Foot Defroster
95% 5% —
60% 40% —
—7 0% 3 0%
—6 0% 4 0%
—1 0% 9 0%
AWIIA0818ZZ
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AUTOMATIC AIR CONDITIONER SYSTEMHAC-17
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Mode door position Air outlet/distribution
Ve n t F o o t
100% —
50% 50%
—1 00 %
WJIA0541E
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HAC-18
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AUTOMATIC AIR CONDITIONER SYSTEM
Switches And Their Cont rol Function (Front)
INFOID:0000000005147679
WJIA1680E
AWIIA0083GB
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AUTOMATIC AIR CONDITIONER SYSTEMHAC-19
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Switches And Their C ontrol Function (Rear)INFOID:0000000005147680
AWIIA0275GB
AWIIA0084GB
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HAC-20
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DIAGNOSIS SYSTEM (HVAC)
DIAGNOSIS SYSTEM (HVAC)
CONSULT-III Function (HVAC)INFOID:0000000005147681
CONSULT-III can display each diagnostic item using the diagnostic test modes shown following.
SELF-DIAGNOSIS
Display Item List
DATA MONITOR
Display Item List
Diagnostic mode
Description
SELF-DIAG RESULTS Displays A/C au to amp. self-diagnosis results.
DATA MONITOR Displays A/C auto amp. input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read. ECU PART NUMBER A/C auto amp. part number can be read.
DTC Description
Reference page
B2573 Battery voltage out of range CHG-8, "
Inspection Procedure"
B2578 In-vehicle sensor circuit out of range (low)
HAC-78, "In-Vehicle Sensor Diagnosis Procedure"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short HAC-75, "
Ambient Sensor Diagnosis Procedure"B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short HAC-81, "
Optical Sensor Diagnosis Procedure".
B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit short HAC-83, "
Intake Sensor Diagnosis Procedure"B2582 Intake sensor circuit open
U1000 CAN bus fault LAN-14, "
Trouble Diagnosis Flow Chart"
Monitor itemValue Contents
BATT VIA CAN "V" Displays battery voltage signal.
IGN VIA CAN "ON/OFF" Displays ignition switch signal.
DVR SUNLD SEN "w/m2" Displays optical sensor (driver) signal.
PAS SUNLD SEN "w/m2" Displays optical sensor (passenger) signal.
AMB TEMP SEN "° C" Displays ambient sensor signal.
EVAP TEMP SEN "° C" Displays intake sensor signal.
INCAR TMP SEN "° C" Displays in-vehicle sensor signal.
RR TEMPSET FR "V" Displays air mix door (front) set point signal.
RR TEMPSET RR "V" Displays air mix door (rear) set point signal.
MODE FDBCK "V" Displays mode door motor feedback signal.
DVR MIX FDBCK "V" Displays air mix door motor (driver) feedback signal.
PAS MIX FDBCK "V" Displays air mix door motor (passenger) feedback signal.
RR FDBCK "V" Displays air mix door motor (rear) feedback signal.
DEF FDBCK "V" Displays defroster door motor feedback signal.
Revision: April 20092010 QX56