air condition INFINITI QX56 2008 Factory Service Manual

HAC-12
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AUTOMATIC AIR CONDITIONER SYSTEM
AUTOMATIC AIR CONDITIONER SYSTEM
Control System DiagramINFOID:0000000001679770
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:0000000001679771
CONTROL OPERATION
AWIIA0088GB
Revision: March 2010 2008 QX56

AUTOMATIC AIR CONDITIONER SYSTEMHAC-13
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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A/C auto amp.
DISPLAY SCREEN
Displays the operational st atus 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, blower 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. Also 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
Revision: March 2010 2008 QX56

HAC-14
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AUTOMATIC AIR CONDITIONER SYSTEM
Rear Air Controls
REAR TEMPERATURE CONTROL DIAL (FRONT/REAR)
The temperature increases or decreases 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 co mpressor 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)
AWIIA0089GB
Revision: March 2010 2008 QX56

AUTOMATIC AIR CONDITIONER SYSTEMHAC-15
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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:0000000001679772
Discharge Air Flow (Rear)INFOID:0000000001679773

Mode door position Air outlet/distribution
Vent Foot Defroster
95% 5% —
60% 40% —
—7 0% 3 0%
—6 0% 4 0%
—1 0% 9 0%
AWIIA0818ZZ
Revision: March 2010 2008 QX56

HAC-16
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AUTOMATIC AIR CONDITIONER SYSTEM
Mode door positionAir outlet/distribution
Vent Foot
100% —
50% 50%
—1 00 %
WJIA0541E
Revision: March 2010 2008 QX56

AUTOMATIC AIR CONDITIONER SYSTEMHAC-17
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Switches And Their Cont rol Function (Front) INFOID:0000000001679774
WJIA1680E
AWIIA0083GB
Revision: March 2010 2008 QX56

HAC-18
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AUTOMATIC AIR CONDITIONER SYSTEM
Switches And Their Control Function (Rear)
INFOID:0000000001679775
AWIIA0275GB
AWIIA0084GB
Revision: March 2010 2008 QX56

CAN COMMUNICATION SYSTEMHAC-19
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CAN COMMUNICATION SYSTEM
System DescriptionINFOID:0000000001679776
Refer to LAN-4, "System Description".
Revision: March 2010 2008 QX56

HAC-20
< FUNCTION DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
DIAGNOSIS SYSTEM (HVAC)
DIAGNOSIS SYSTEM (HVAC)
CONSULT-III Function (HVAC)INFOID:0000000001679777
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-10, "
Inspection Procedure"
B2578 In-vehicle sensor circuit out of range (low)
HAC-81, "In-Vehicle Sensor Diagnosis Procedure"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short HAC-78, "
Ambient Sensor Diagnosis Procedure"B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short HAC-84, "
Optical Sensor Diagnosis Procedure".
B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit short HAC-86, "
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: March 2010 2008 QX56

DIAGNOSIS SYSTEM (BCM)HAC-21
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DIAGNOSIS SYSTEM (BCM)
CONSULT-III Function (BCM)INFOID:0000000001679778
CONSULT-III can display each diagnostic item us ing the diagnostic test modes shown following.
DATA MONITOR
Display Item List
BCM diagnostic
test item Diagnostic mode
Description
Inspection by part WORK SUPPORT
Supports inspections and adjustments. Commands are transmitted to the BCM for
setting the status suitable for required operation, input/output signals are received
from the BCM and received data is displayed.
DATA MONITOR Displays BCM input/output data in real time. ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
SELF-DIAG RESULTS Displays BCM self-diagnosis results.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read. ECU PART NUMBER BCM part number can be read.
CONFIGURATION Performs BCM configuration read/write functions.
Monitor item name “operation or unit” Contents
IGN ON SW “ON/OFF” Displays “IGN Position (ON)/OFF, ACC Position (OFF)” status as judged from ignition switch signal.
COMP ON SIG “ON/OFF” Displays “COMP (ON)/COMP (OFF)” stat us as judged from air conditioner switch signal.
FAN ON SIG “ON/OFF” Displays “FAN (ON)/FAN (OFF)” status as judged from blower motor switch signal.
Revision: March 2010 2008 QX56