2007 INFINITI QX56 sensor

ATC-4
< SERVICE INFORMATION >
PRECAUTIONS
not have dedicated recovery equipment, you may contact a local refrigerant product retailer for available ser-
vice. This refrigerant must be disposed of in acco rdance with all federal and local regulations. In addition,
replacement of all refrigerant system components on the vehicle is recommended.
• If the vehicle is within the warranty period, the air conditioner warranty is void. Please contact NISSAN Cus-
tomer Affairs for further assistance.
General Refrigerant PrecautionINFOID:0000000003533220
WARNING:
• Do not release refrigerant into th e air. Use approved recovery/recycling equipment to capture the
refrigerant every time an air conditioning system is discharged.
• Always wear eye and hand protection (goggles and gloves) when working with any refrigerant or air
conditioning system.
• Do not store or heat refrigerant containers above 52 °C (125 °F).
• Do not heat a refrigerant container with an open flame; if container warming is required, place the
bottom of the container in a warm pail of water.
• Do not intentionally drop, puncture, or incinerate refrigerant containers.
• Keep refrigerant away from open flames: poisonou s gas will be produced if refrigerant burns.
• Refrigerant will displace oxygen, therefore be certa in to work in well ventilated areas to prevent suf-
focation.
• Do not pressure test or leak test HFC-134a (R-134a) service equipment and/or vehicle air condition-
ing systems with compressed air during repair. Some mixtures of air and HFC-134a (R-134a) have
been shown to be combustible at elevated pressures. These mixtures, if ignited, may cause injury or
property damage. Additional heal th and safety information may be obtained from refrigerant manu-
facturers.
Precaution for Leak Detection DyeINFOID:0000000003533221
• The A/C system contains a fluorescent leak detection dye used for locating refrigerant leaks. An ultraviolet
(UV) lamp is required to illuminate the dye when inspecting for leaks.
• Always wear fluorescence enhancing UV safety goggles to protect your eyes and enhance the visibility of
the fluorescent dye.
• The fluorescent dye leak detector is not a replacement for an electronic refrigerant leak detector. The fluo-
rescent dye leak detector should be used in conjuncti on with an electronic refrigerant leak detector (J-
41995).
• For your safety and the customer's satisfaction, r ead and follow all manufacturer's operating instructions and
precautions prior to performing work.
• A compressor shaft seal should not be repaired because of dye seepage. The compressor shaft seal should only be repaired after confirming the leak with an electronic refrigerant leak detector (J-41995).
• Always remove any dye from the leak area after repairs are complete to avoid a misdiagnosis during a future
service.
• Do not allow dye to come into contact with painted body panels or interior components. If dye is spilled,
clean immediately with the approved dye cleaner. Fluoresc ent dye left on a surface for an extended period of
time cannot be removed .
• Do not spray the fluorescent dye cleaning agent on hot surfaces (engine exhaust manifold, etc.).
• Do not use more than one refrigerant dye bottle (1/4 ounce / 7.4 cc) per A/C system.
• Leak detection dyes for HFC-134a (R-134a) and CFC-12 (R -12) A/C systems are different. Do not use HFC-
134a (R-134a) leak detection dye in CFC-12 (R-12) A/ C systems or CFC-12 (R-12) leak detection dye in
HFC-134a (R-134a) A/C systems or A/C system damage may result.
• The fluorescent properties of the dye will remain for ov er three (3) years unless a compressor failure occurs.
A/C Identification LabelINFOID:0000000003533222
Vehicles with factory installed fluorescent dye have this identification label on the underside of hood.
Precaution for Refrigerant ConnectionINFOID:0000000003533223
A new type refrigerant connection has been introduced to al l refrigerant lines except the following locations.
• Expansion valve to cooling unit
• Evaporator pipes to evaporator (inside cooling unit)
• Refrigerant pressure sensor
FEATURES OF NEW TYPE REFRIGERANT CONNECTION

ATC-6
< SERVICE INFORMATION >
PRECAUTIONS
Front A/C Compressor and Condenser
WJIA1578E
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

ATC-16
< SERVICE INFORMATION >
REFRIGERATION SYSTEM
REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000003533229
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 exter nally equalized expansion valves, located inside the front
and rear evaporator cases.
Refrigerant System ProtectionINFOID:0000000003533230
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rise s above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside t he 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).
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 incr eases to an abnormal level [more than 2,990 kPa (30.5 kg/

ATC-22
< SERVICE INFORMATION >
AIR CONDITIONER CONTROL
AIR CONDITIONER CONTROL
DescriptionINFOID:0000000003533233
The front air control provides automatic regulation of the vehicle's interior temperature. The system is based
on the driver's and passenger's selected "set temperat ure", regardless of the outside temperature changes.
This is done by utilizing a microcomputer, also referred to as the front air control, which receives input signals
from the following seven sensors:
• Ambient sensor
• In-vehicle sensor
• Intake sensor
• Optical sensor (providing one input for driver and one input for passenger side)
• PBR (Position Balanced Resistor)
• Vehicle speed sensor (via CAN communication)
• Engine coolant temperature (via CAN communication)
The front air control uses these signals (including the set temperature) to automatically control:
• Outlet air volume
• Air temperature
• Air distribution
The front air control also provides separate regulation of the vehicle's interior temperature for the rear passen-
ger area. The system is based on the temperature and r ear blower settings selected from rear control
switches located on the front air control, or from the temperature and rear blower settings selected from rear
control switches on the rear air control, when the front air control switches are set to the rear position.
The front air control is used to select: • Outlet air volume
• Air temperature/distribution
OperationINFOID:0000000003533234
AIR MIX DOORS CONTROL
The air mix doors are automatically controlled so that in-vehicle temperature is maintained at a predetermined
value by the temperature setting, ambient temper ature, in-vehicle temperature and amount of sunload.
BLOWER SPEED CONTROL
Blower speed is automatically controlled by the temperat ure setting, ambient temperature, in-vehicle tempera-
ture, intake temperature, amount of sunload and air mix door position.
When AUTO switch is pressed, the blower motor starts to gradually increase air flow volume (if required).
When engine coolant temperature is low, the blower moto r operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake door is automatically controlled by the tem perature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunl oad and by the ON-OFF operation of the compressor.
MODE DOOR CONTROL
The mode door is automatically controlled by the temperat ure setting, ambient temperature, in-vehicle temper-
ature, intake temperature and amount of sunload.
DEFROSTER DOOR CONTROL
The defroster door is controlled by: Turning the defroster dial to front defroster.

AIR CONDITIONER CONTROLATC-23
< SERVICE INFORMATION >
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MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, front air control inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM and front air control 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.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
SELF-DIAGNOSTIC SYSTEM
The self-diagnostic system is built into the front air cont rol to quickly locate the cause of symptoms. Refer to
ATC-48, "
A/C System Self-Diagnosis Function"
Description of Control SystemINFOID:0000000003533235
The control system consists of input sensors, swit ches, the front air control (microcomputer) and outputs.
WJIA2144E

ATC-30
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
TROUBLE DIAGNOSIS
CONSULT-II Function (HVAC)INFOID:0000000003533241
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II START PROCEDURE
Refer to GI-36, "CONSULT-II Start Procedure".
SELF-DIAGNOSIS
Display Item List
DATA MONITOR
Display Item List
Diagnostic mode Description
SELF-DIAG RESULTS Displays front ai r control self-diagnosis results.
DATA MONITOR Displays front air control 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 Front air control part number can be read.
DTC Description Reference page
B2573 Battery voltage out of range SC-4
B2578 In-vehicle sensor circuit out of range (low)
AT C - 11 6 , "In-vehicle Sensor Circuit"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short AT C - 11 4
B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short AT C - 11 9 , "
Optical Sensor Circuit"B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit shortATC-120, "
Intake Sensor Circuit"B2582 Intake sensor circuit open
U1000 CAN bus fault LAN-4, "
CAN Communication System"
B2587 Stuck buttonATC-123, "Removal and Installation"
Monitor item Value 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/ °F" Displays ambient sensor 1 signal.
EVAP TEMP SEN " °C/ °F" Displays intake sensor signal.
INCAR TMP SEN " °C/ °F" Displays in-vehicle sensor signal.
RR TEMPSET FR "V" Displays air mix door (front) set point signal.
RR TEMPSET RR "V" Displays air mi x door (rear) set point signal.
MODE FDBCK "V" Displays mode door motor feedback signal.
DVR MIX FDBCK "V" Displays air mix do or 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.

TROUBLE DIAGNOSISATC-33
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FRONT PASSENGER COMPARTMENT
1 Water Valve F68 2 Refrigerant pressure sensor E48 3 Ambient sensor E1
4 A/C Compressor F3
WJIA1912E

ATC-34
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
1 Front air control M49, M50 2 Rear blower switch (front) M52 3 In-vehicle sensor M32
4 Intake sensor M146 5 Intake door motor M58 6 Variable blower control M122
7 Air mix door motor (passenger) M143 8 Mode door motor M142 9 Defroster door motor M144
10 Air mix door motor (driver) M147 11 Optical sensor M402
WJIA1969E