sensor INFINITI QX56 2004 Factory Service Manual

ATC-4Revision: August 20072004 QX56 Removal and Installation for Low-pressure Pipe ..171
REMOVAL .........................................................171
INSTALLATION ..................................................171
Removal and Installation for Rear High- and Low-
pressure A/C and Heater Core Pipes ...................171
REMOVAL .........................................................171
INSTALLATION ..................................................172
Removal and Installation for Underfloor Rear High-
and Low-pressure A/C and Heater Core Pipes ....172
REMOVAL .........................................................172
INSTALLATION ..................................................173
Removal and Installation for Refrigerant Pressure
Sensor ..................................................................173
REMOVAL .........................................................173
INSTALLATION ..................................................173
Removal and Installation for Condenser ...............173
REMOVAL .........................................................173
INSTALLATION ..................................................174
Removal and Installation for Front Evaporator .....175
REMOVAL .........................................................175
INSTALLATION ..................................................176
Removal and Installation for Rear Evaporator ......176
REMOVAL .........................................................177INSTALLATION .................................................. 177
Removal and Installation for Front Expansion Valve . 177
REMOVAL .......................................................... 177
INSTALLATION .................................................. 177
Removal and Installation for Rear Expansion Valve . 177
REMOVAL .......................................................... 177
INSTALLATION .................................................. 178
Checking for Refrigerant Leaks ............................ 178
Checking System for Leaks Using the Fluorescent
Dye Leak Detector ................................................ 178
Dye Injection ......................................................... 178
Electronic Refrigerant Leak Detector .................... 179
PRECAUTIONS FOR HANDLING LEAK
DETECTOR ....................................................... 179
CHECKING PROCEDURE ................................ 180
SERVICE DATA AND SPECIFICATIONS (SDS) .... 182
Service Data and Specifications (SDS) ................ 182
COMPRESSOR ................................................. 182
LUBRICANT ....................................................... 182
REFRIGERANT ................................................. 182
ENGINE IDLING SPEED ................................... 182
BELT TENSION ................................................. 182

PRECAUTIONS
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Revision: August 20072004 QX56
A/C Identification LabelEJS002BK
Vehicles with factory installed fluorescent dye have this identification
label on the underside of hood.
Precautions for Refrigerant ConnectionEJS002BL
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.
WJIA0672E
SHA8 15 E

PRECAUTIONS
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Revision: August 20072004 QX56
Rear A/C
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
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 motor 6. 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 size E. 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: August 20072004 QX56
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleEJS002BS
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 ProtectionEJS002BT
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 deenergizes 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).

ATC-24
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
AIR CONDITIONER CONTROLPFP:27500
DescriptionEJS002BW
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 that is part of the front air control, which receives input signals from
the following five sensors:

Ambient sensor

In-vehicle sensor

Intake sensor

Optical sensor (one sensor for driver and passenger side)

PBR (position balanced resistor)
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 on the front air control
rear fan switch (front) and rear temperature/mode dial (front), or from the rear fan switch (rear) and rear tem-
perature/mode dial (rear) on the rear air control, when the rear fan switch (front) is set to the rear (R) position.
The front air control or rear air control is used to select:

Outlet air volume

Air temperature/mode distribution
OperationEJS002BX
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.
FAN SPEED CONTROL
Blower speed is automatically controlled based on temperature setting, ambient temperature, in-vehicle tem-
perature, 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 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.

AIR CONDITIONER CONTROL
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Revision: August 20072004 QX56
MAGNET CLUTCH CONTROL
When the A/C or DEF switch is activated, the front air control outputs a compressor ON signal to the BCM.
Upon receiving this input, the BCM sends a compressor ON signal to the ECM via CAN communication lines.
The ECM then judges whether the compressor can be turned ON, based on each sensor status (refrigerant
pressure sensor signal, throttle angle sensor, etc.). If it determines the compressor can be turned ON, a com-
pressor ON signal is sent to the IPDM E/R via CAN communication lines.
Upon receipt of a compressor ON signal, the IPDM E/R turns ON the A/C relay which engages the magnet
clutch and operates the A/C compressor.
SELF-DIAGNOSTIC SYSTEM
A self-diagnostic system is built into the front air control to quickly locate the cause of symptoms. Refer to
ATC-53, "
A/C System Self-diagnosis Function"
WJIA0751E

ATC-26
AIR CONDITIONER CONTROL
Revision: August 20072004 QX56
Description of Control SystemEJS002BY
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 OperationEJS002BZ
Front air control
WJIA0755E
WJIA0756E

TROUBLE DIAGNOSIS
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Front Air Control Terminals and Reference ValueEJS002C9
Measure voltage between each terminal and ground by following
Terminals and Reference Value for Front Air Control.
PIN CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUE FOR FRONT AIR CONTROL
WJIA0759E
WJIA0402E
Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
1 B Ground - - 0V
2YPower supply for each door motor
PBRON - 0 - 5V
3 W/G Air mix door motor (Driver) CW ON Clockwise rotation Battery voltage
4 G Air mix door motor (Driver) CCW ON Counterclockwise rotation Battery voltage
5 BR/W Mode door motor CW ON Clockwise rotation Battery voltage
6 P/L Mode door motor CCW ON Counterclockwise rotation Battery voltage
7 O Intake door motor CCW ON Counterclockwise rotation Battery voltage
8 G/B Intake door motor CW ON Clockwise rotation Battery voltage
9 L/B Intake sensor ON - 0 - 5V
10 L/R Fan ON signal ONFan switch OFF 5V
Fan switch ON 0V
11 Y/B Rear defroster request ON - Battery voltage
12 W/R Compressor ON signal ONA/C switch OFF 5V
A/C switch ON 0V
13 G/R Variable blower control ON - 0 - 5V
14 Y/G Power supply for IGN ON - Battery voltage
15 P Ground for each door motor PBR ON - 0 - 5V
16 GR Mode door motor PBR feedback ON - 0 - 5V
17 P Ambient sensor ON - 0 - 5V
18 SBAir mix door motor (Driver) PBR
feedbackON - 0 - 5V
19 LG Defroster door motor CW ON Clockwise rotation Battery voltage
20 P/B Defroster door motor CCW ON Counterclockwise rotation Battery voltage

ATC-52
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
21 V/R Sensor ground ON - 0 - 5V
22 Y/R Power supply for BAT - - Battery voltage
23 R/L Power supply for illumination ON Park lamps ON Battery voltage
24 BR Illumination ground - Park lamps ON
25 LG/B Defroster door motor feedback ON - 0 - 5V
26 R/B Front blower motor request ONFront blower motor OFF Battery voltage
Front blower motor ON 0V
27 GR/R Air mix door motor (Rear) CW ON Clockwise rotation Battery voltage
28 L/Y Air mix door motor (Rear) CCW ON Counterclockwise rotation Battery voltage
29 W/G Water valve ONWater valve open 0V
Water valve closed 5V
31 W/V Optical sensor (Passenger) ON - 0 - 5V
32 LG/R In-vehicle sensor signal ON - 0 - 5V
33 V Air mix door motor (Rear) set point ON - 0 - 5V
34 W CAN-H ON - -
35 R CAN-L ON - -
36 G/W Air mix door motor (Passenger) CW ON Clockwise rotation Battery voltage
37 LAir mix door motor (Passenger)
CCWON Counter clockwise rotation Battery voltage
38 W/L Rear blower motor request ONRear blower motor OFF Battery voltage
Rear blower motor ON 0V
39 Y/B Rear select signal ON - 0 - 5V
40 G/O Optical sensor (Driver) ON - 0 - 5V
41 R/WAir mix door motor (Passenger) PBR
feedbackON - 0 - 5V
42 R/YAir mix door motor (Rear) PBR feed-
backON - 0 - 5V
43 BR/Y In-vehicle sensor motor (power) ON - Battery voltage
44 O/B In-vehicle sensor motor (ground) ON - 0V Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
PIIA2344E

TROUBLE DIAGNOSIS
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Revision: August 20072004 QX56
A/C System Self-diagnosis FunctionEJS002CA
DESCRIPTION
Using Front Air Control Switches
NOTE:
Ambient temperature must be at least 10° C (50° F) to run self-diagnosis.
The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. Refer to applicable sections
(items) for details. Shifting from usual control to the self-diagnostic system is accomplished by turning the igni-
tion switch ON and pressing the fan (down) switch while turning the passenger temperature dial in either direc-
tion (hold momentarily). Within 3 seconds of doing this, press the AUTO switch. The front blower speed
indication bars will flash and the ambient temperature display will indicate 0° during the self-diagnosis. Fault
codes (if any are present) will be displayed in the ambient temperature display area. Refer to AT C - 5 5 , "
SELF-
DIAGNOSIS CODE CHART" .
WJIA0837E