2006 INFINITI QX56 sensor

ATC-4Revision: November 20092006 QX56
Removal and Installation for Low-pressure Pipe .
.180
REMOVAL ........................................................ .180
INSTALLATION ................................................. .180
Removal and Installation for Rear High- and Low-
pressure A/C and Heater Core Pipes .................. .180
REMOVAL ........................................................ .180
INSTALLATION ................................................. .181
Removal and Installation for Underfloor Rear High-
and Low-pressure A/C and Heater Core Pipes ... .181
REMOVAL ........................................................ .181
INSTALLATION ................................................. .182
Removal and Installation for Refrigerant Pressure
Sensor ................................................................. .182
REMOVAL ........................................................ .182
INSTALLATION ................................................. .182
Removal and Installation for Condenser .............. .182
REMOVAL ........................................................ .182
INSTALLATION ................................................. .183
Removal and Installation for Front Evaporator .... .184
REMOVAL ........................................................ .184
INSTALLATION ................................................. .185
Removal and Installation for Rear Evaporator ..... .185
REMOVAL ........................................................ .186INSTALLATION .................................................
.186
Removal and Installation for Front Expansion Valve .186
REMOVAL ......................................................... .186
INSTALLATION ................................................. .186
Removal and Installation for Rear Expansion Valve .186
REMOVAL ......................................................... .186
INSTALLATION ................................................. .187
Checking for Refrigerant Leaks ........................... .187
PRELIMINARY CHECK .................................... .187
Checking System for Leaks Using the Fluorescent
Dye Leak Detector ............................................... .187
Dye Injection ........................................................ .187
Electronic Refrigerant Leak Detector ................... .188
PRECAUTIONS FOR HANDLING LEAK
DETECTOR ...................................................... .188
CHECKING PROCEDURE ............................... .189
SERVICE DATA AND SPECIFICATIONS (SDS) ... .191
Service Data and Specifications (SDS) ............... .191
COMPRESSOR ................................................ .191
OIL .................................................................... .191
REFRIGERANT ................................................ .191
ENGINE IDLING SPEED .................................. .191
BELT TENSION ................................................ .191

PRECAUTIONSATC-7
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Revision: November 2009 2006 QX56
Precautions for Refrigerant ConnectionEJS003WU
A new type refrigerant connection has been introduced to all 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

The O-ring has been relocated. It has also been provided with a groove for proper installation. This
reduces the possibility of the O-ring being caught in, or damaged by, the mating part. The sealing direction
of the O-ring is now set vertically in relation to the contacting surface of the mating part to improve sealing
characteristics.

The reaction force of the O-ring will not occur in the direction that causes the joint to pull out, thereby facil-
itating piping connections.
SHA815E

PRECAUTIONSATC-9
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Rear A/C
1. High-pressure service valve 2. Grommet3. 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
WJIA2315E
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 specifications 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.

ATC-18
REFRIGERATION SYSTEM
Revision: November 20092006 QX56
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleEJS003X1
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 ProtectionEJS003X2
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 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 pressure 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).

AIR CONDITIONER CONTROLATC-25
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AIR CONDITIONER CONTROLPFP:27500
DescriptionEJS003X5
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 temperature", 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 rear 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
OperationEJS003X6
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 temperature, in-vehicle temperature and amount of sunload.
BLOWER SPEED CONTROL
Blower speed is automatically controlled by the temperature 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 motor operation is delayed to prevent cool air from flow-
ing.
INTAKE DOOR CONTROL
The intake door is automatically controlled by the temperature setting, ambient temperature, in-vehicle tem-
perature, intake temperature, amount of sunload and by the ON-OFF operation of the compressor.
MODE DOOR CONTROL
The mode door is automatically controlled by the temperature 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.

ATC-26
AIR CONDITIONER CONTROL
Revision: November 20092006 QX56
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, 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 control to quickly locate the cause of symptoms. Refer to
AT C - 5 6 , "
A/C System Self-diagnosis Function"
WJIA1163E

AIR CONDITIONER CONTROLATC-27
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Description of Control SystemEJS003X7
The control system consists of input sensors, switches, the front air control (microcomputer) and outputs.
The relationship of these components is shown in the figure below:
Control OperationEJS003X8
Front air control
WJIA1917E
WJIA1714E

TROUBLE DIAGNOSISATC-35
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SELF-DIAGNOSIS
Operation Procedure
1. Touch “SELF-DIAG RESULTS ” on “SELECT DIAG MODE”
screen to view all set DTC's.
Display Item List
DATA MONITOR
Operation Procedure
1. Touch “DATA MONITOR ” on “SELECT DIAG MODE ” screen.
2. Touch either “MAIN SIGNALS” or “SELECTION FROM MENU ” on “DATA MONITOR” screen.
3. When “SELECTION FROM MENU ” is selected, touch items to be monitored. When “MAIN SIGNALS” is
selected, all the items will be monitored.
4. Touch “START”.
5. Touch “RECORD” while monitoring, then the status of the monitored item can be recorded. To stop
recording, touch “STOP”.
BCIA0031E
DTC Description
Reference page
B2573 Battery voltage out of range SC-4, "
BATTERY"
B2578 In-vehicle sensor circuit out of range (low)
ATC-137, "In-vehicle Sensor Circuit"B2579 In-vehicle sensor circuit out of range (high)
B257B Ambient sensor circuit short ATC-134, "
Ambient Sensor Circuit"B257C Ambient sensor circuit open
B257F Optical sensor (Driver) circuit open or short ATC-140, "
Optical Sensor Circuit"B2580 Optical sensor (Passenger) circuit open or short
B2581 Intake sensor circuit shortATC-142, "
Intake Sensor Circuit"B2582 Intake sensor circuit open
U1000 CAN bus fault LAN-26, "
CAN COMMUNICATION"
B2587 Stuck buttonATC-144, "FRONT AIR CONTROL"
BCIA0031E
MAIN SIGNALSMonitors all the items.
SELECTION FROM MENU Selects and monitors the individual item selected.