2006 INFINITI QX56 blower

ATC-1
AUTOMATIC AIR CONDITIONER
J AIR CONDITIONER
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Revision: November 2009 2006 QX56
PRECAUTIONS .....................................................
..... 5
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ............................................................. ..... 5
Precautions for Working with HFC-134a (R-134a) ..... 5
Contaminated Refrigerant ................................... ..... 5
General Refrigerant Precautions ......................... ..... 6
Precautions for Leak Detection Dye .................... ..... 6
A/C Identification Label ....................................... ..... 6
Precautions for Refrigerant Connection .............. ..... 7
FEATURES OF NEW TYPE REFRIGERANT
CONNECTION ................................................. ..... 7
O-RING AND REFRIGERANT CONNECTION ..... 8
Precautions for Servicing Compressor ................ .... 11
Precautions for Service Equipment ..................... .... 11
RECOVERY/RECYCLING EQUIPMENT ......... .... 11
ELECTRONIC LEAK DETECTOR ................... .... 11
VACUUM PUMP .............................................. ... 12
MANIFOLD GAUGE SET ................................. ... 12
SERVICE HOSES ............................................ ... 12
SERVICE COUPLERS ..................................... ... 13
REFRIGERANT WEIGHT SCALE ................... ... 13
CHARGING CYLINDER ................................... ... 13
PREPARATION ...................................................... ... 14
Special Service Tools .......................................... ... 14
HFC-134a (R-134a) Service Tools and Equipment ... 14
Commercial Service Tools ................................... ... 17
REFRIGERATION SYSTEM .................................. ... 18
Refrigerant Cycle ................................................ ... 18
REFRIGERANT FLOW .................................... ... 18
Refrigerant System Protection ............................ ... 18
REFRIGERANT PRESSURE SENSOR .......... ... 18
PRESSURE RELIEF VALVE ............................ ... 19
Component Layout .............................................. ... 20
FRONT REFRIGERATION SYSTEM ............... ... 20
REAR REFRIGERATION SYSTEM ................. ... 21
OIL ......................................................................... ... 22
Maintenance of Oil Quantity in Compressor ....... ... 22
OIL ................................................................... ... 22
CHECKING AND ADJUSTING ........................ ... 22AIR CONDITIONER CONTROL ............................
... 25
Description ........................................................... ... 25
Operation ............................................................. ... 25
AIR MIX DOORS CONTROL ........................... ... 25
BLOWER SPEED CONTROL .......................... ... 25
INTAKE DOOR CONTROL .............................. ... 25
MODE DOOR CONTROL ................................ ... 25
DEFROSTER DOOR CONTROL ..................... ... 25
MAGNET CLUTCH CONTROL ........................ ... 26
SELF-DIAGNOSTIC SYSTEM ......................... ... 26
Description of Control System ............................. ... 27
Control Operation ................................................... 27 DISPLAY SCREEN .............................................. 28
AUTO SWITCH ................................................ ... 28
TEMPERATURE CONTROL DIAL (TEMPERA-
TURE CONTROL) (DRIVER SIDE) .................. ... 28
TEMPERATURE CONTROL DIAL (TEMPERA-
TURE CONTROL) (PASSENGER SIDE) ......... ... 28
TEMPERATURE CONTROL DIAL (TEMPERA-
TURE AND MODE CONTROL) (REAR) .......... ... 28
RECIRCULATION () SWITCH .......................... ... 28
DEFROSTER () SWITCH ................................. ... 28
REAR WINDOW DEFOGGER SWITCH .......... ... 28
OFF SWITCH ................................................... ... 28
A/C SWITCH .................................................... ... 28
MODE SWITCH (FRONT) ................................ ... 28
FRONT BLOWER CONTROL DIAL ................. ... 28
TEMPERATURE CONTROL DIAL (TEMPERA-
TURE AND MODE CONTROL) ........................ ... 29
REAR BLOWER CONTROL DIAL ................... ... 29
Discharge Air Flow ................................................. 30 FRONT ............................................................. ... 30
REAR ............................................................... ... 30
System Description (Front) .................................. ... 31
SWITCHES AND THEIR CONTROL FUNCTION ... 31
System Description (Rear) .................................. ... 32
SWITCHES AND THEIR CONTROL FUNCTION ... 32
CAN Communication System Description ........... ... 33
TROUBLE DIAGNOSIS ......................................... ... 34
CONSULT-II Function (HVAC) ............................. ... 34

ATC-2Revision: November 20092006 QX56
CONSULT-II BASIC OPERATION ....................
... 34
SELF-DIAGNOSIS ........................................... ... 35
DATA MONITOR ............................................... ... 35
CONSULT-II Function (BCM) ............................... ... 37
CONSULT-II BASIC OPERATION .................... ... 37
DATA MONITOR ............................................... ... 38
How to Perform Trouble Diagnosis for Quick and
Accurate Repair ................................................... ... 39
WORK FLOW ................................................... ... 39
SYMPTOM TABLE ........................................... ... 39
Component Parts and Harness Connector Location ... 40
ENGINE COMPARTMENT ............................... ... 40
FRONT PASSENGER COMPARTMENT ......... ... 41
REAR PASSENGER COMPARTMENT ............... 42
Schematic ............................................................ ... 43
Wiring Diagram — A/C,A — ................................ ... 44
Front Air Control Terminals and Reference Value ... 54
PIN CONNECTOR TERMINAL LAYOUT ......... ... 54
TERMINALS AND REFERENCE VALUE FOR
FRONT AIR CONTROL .................................... ... 54
A/C System Self-diagnosis Function ................... ... 56
DESCRIPTION ................................................. ... 56
Operational Check (Front) ................................... ... 58
CHECKING MEMORY FUNCTION .................. ... 58
CHECKING BLOWER ...................................... ... 58
CHECKING DISCHARGE AIR ......................... ... 58
CHECKING RECIRCULATION (, ONLY) .......... ... 58
CHECKING TEMPERATURE DECREASE ...... ... 58
CHECKING TEMPERATURE INCREASE ....... ... 59
CHECK A/C SWITCH ....................................... ... 59
CHECKING AUTO MODE ................................ ... 59
Operational Check (Rear) .................................... ... 60
CHECKING BLOWER ...................................... ... 60
CHECKING TEMPERATURE DECREASE ...... ... 60
CHECKING TEMPERATURE INCREASE ....... ... 60
Power Supply and Ground Circuit for Front Air Con-
trol ........................................................................ ... 61
INSPECTION FLOW ........................................ ... 61
COMPONENT DESCRIPTION ......................... ... 62
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM ... 62
Mode Door Motor Circuit ........................................ 64 INSPECTION FLOW ........................................ ... 64
SYSTEM DESCRIPTION ................................. ... 65
COMPONENT DESCRIPTION ......................... ... 66
DIAGNOSTIC PROCEDURE FOR MODE
DOOR MOTOR ................................................ ... 66
Air Mix Door Motor Circuit ................................... ... 70
INSPECTION FLOW ........................................ ... 70
SYSTEM DESCRIPTION ................................. ... 71
COMPONENT DESCRIPTION ......................... ... 72
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (DRIVER) ................................ ... 72
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER) ....................... ... 76
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (REAR) ................................... ... 79
Intake Door Motor Circuit ..................................... ... 83
INSPECTION FLOW ........................................ ... 83
SYSTEM DESCRIPTION ................................. ... 84COMPONENT DESCRIPTION .........................
... 85
DIAGNOSTIC PROCEDURE FOR INTAKE
DOOR MOTOR ................................................. ... 85
Defroster Door Motor Circuit ................................ ... 87
SYMPTOM: ....................................................... ... 87
INSPECTION FLOW ......................................... ... 87
SYSTEM DESCRIPTION .................................. ... 88
COMPONENT DESCRIPTION ......................... ... 88
DIAGNOSTIC PROCEDURE FOR
DEFROSTER DOOR MOTOR .......................... ... 89
Front Blower Motor Circuit ................................... ... 93
INSPECTION FLOW ......................................... ... 93
SYSTEM DESCRIPTION .................................. ... 94
COMPONENT DESCRIPTION ......................... ... 95
DIAGNOSTIC PROCEDURE FOR BLOWER
MOTOR ............................................................. ... 95
COMPONENT INSPECTION ............................ .100
Rear Blower Motor Circuit .................................... .101
INSPECTION FLOW ......................................... .101
SYSTEM DESCRIPTION .................................. .102
DIAGNOSTIC PROCEDURE FOR REAR
BLOWER MOTOR ............................................ .102
COMPONENT INSPECTION ............................ .110
Rear Air Control Circuit ........................................ .112
INSPECTION FLOW ......................................... .112
SYSTEM DESCRIPTION .................................. .113
DIAGNOSTIC PROCEDURE FOR REAR AIR
CONTROL ........................................................ .113
Magnet Clutch Circuit ........................................... .115
INSPECTION FLOW ......................................... .115
SYSTEM DESCRIPTION .................................. .116
DIAGNOSTIC PROCEDURE FOR MAGNET
CLUTCH ........................................................... .116
Insufficient Cooling ............................................... .121
INSPECTION FLOW ......................................... .121
PERFORMANCE TEST DIAGNOSES ............. .122
PERFORMANCE CHART ................................. .124
TROUBLE DIAGNOSES FOR UNUSUAL PRES-
SURE ................................................................ .125
Insufficient Heating .............................................. .128
INSPECTION FLOW ......................................... .128
Noise .................................................................... .129
INSPECTION FLOW ......................................... .129
Self-diagnosis ...................................................... .130
INSPECTION FLOW ......................................... .130
Memory Function ................................................. .131
INSPECTION FLOW ......................................... .131
Water Valve Circuit ............................................... .132
COMPONENT DESCRIPTION ......................... .132
DIAGNOSTIC PROCEDURE FOR WATER
VALVE ............................................................... .132
Ambient Sensor Circuit ........................................ .134
COMPONENT DESCRIPTION ......................... .134
AMBIENT TEMPERATURE INPUT PROCESS .134
DIAGNOSTIC PROCEDURE FOR AMBIENT
SENSOR ........................................................... .134
COMPONENT INSPECTION ............................ .136
In-vehicle Sensor Circuit ...................................... .137
COMPONENT DESCRIPTION ......................... .137

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DIAGNOSTIC PROCEDURE FOR IN-VEHICLE
SENSOR ..........................................................
. 138
COMPONENT INSPECTION ........................... . 140
Optical Sensor Circuit ......................................... . 140
COMPONENT DESCRIPTION ........................ . 140
OPTICAL INPUT PROCESS ........................... . 140
DIAGNOSTIC PROCEDURE FOR OPTICAL
SENSOR .......................................................... . 141
Intake Sensor Circuit ........................................... . 142
COMPONENT DESCRIPTION ........................ . 142
DIAGNOSTIC PROCEDURE FOR INTAKE SEN-
SOR ................................................................. . 142
COMPONENT INSPECTION ........................... . 143
CONTROL UNIT .................................................... . 144
Removal and Installation ..................................... . 144
FRONT AIR CONTROL ................................... . 144
REAR AIR CONTROL ...................................... . 144
AMBIENT SENSOR ............................................... . 145
Removal and Installation ..................................... . 145
REMOVAL ........................................................ . 145
INSTALLATION ................................................ . 145
IN-VEHICLE SENSOR ........................................... . 146
Removal and Installation ..................................... . 146
REMOVAL ........................................................ . 146
INSTALLATION ................................................ . 146
OPTICAL SENSOR ............................................... . 147
Removal and Installation ..................................... . 147
INTAKE SENSOR .................................................. . 148
Removal and Installation ..................................... . 148
REMOVAL ........................................................ . 148
INSTALLATION ................................................ . 148
BLOWER MOTOR ................................................. . 149
Components ........................................................ . 149
Removal and Installation ..................................... . 149
FRONT BLOWER MOTOR .............................. . 149
REAR BLOWER MOTOR ................................ . 150
IN-CABIN MICROFILTER ...................................... . 151
Removal and Installation ..................................... . 151
FUNCTION ....................................................... . 151
REPLACEMENT TIMING ................................. . 151
REPLACEMENT PROCEDURE ...................... . 151
HEATER & COOLING UNIT ASSEMBLY ............. . 153
Components ........................................................ . 153
Removal and Installation ..................................... . 154
FRONT HEATER AND COOLING UNIT ASSEM-
BLY ................................................................... . 154
REAR HEATER AND COOLING UNIT ASSEM-
BLY ................................................................... . 155
HEATER CORE ..................................................... . 156
Components ........................................................ . 156
Removal and Installation ..................................... . 157
FRONT HEATER CORE .................................. . 157
REAR HEATER CORE .................................... . 158
DEFROSTER DOOR MOTOR ............................... . 159
Removal and Installation ..................................... . 159
REMOVAL ........................................................ . 159
INSTALLATION ................................................ . 159INTAKE DOOR MOTOR ........................................
.160
Removal and Installation ..................................... .160
REMOVAL ........................................................ .160
INSTALLATION ................................................ .160
MODE DOOR MOTOR ........................................... .161
Removal and Installation ..................................... .161
REMOVAL ........................................................ .161
INSTALLATION ................................................ .161
AIR MIX DOOR MOTOR ........................................ .162
Components ........................................................ .162
Removal and Installation ..................................... .162
FRONT AIR MIX DOOR MOTOR (DRIVER) .... .162
FRONT AIR MIX DOOR MOTOR (PASSENGER) .163
REAR AIR MIX DOOR MOTOR ....................... .163
VARIABLE BLOWER CONTROL .......................... .164
Removal and Installation ..................................... .164
REMOVAL ........................................................ .164
INSTALLATION ................................................ .164
REAR BLOWER MOTOR RESISTOR ................... .165
Removal and Installation ..................................... .165
REMOVAL ........................................................ .165
INSTALLATION ................................................ .165
DUCTS AND GRILLES .......................................... .166
Components ........................................................ .166
Removal and Installation ..................................... .169
CENTER CONSOLE HEAT DUCT AND REAR
FINISHER ASSEMBLY GRILLE ....................... .169
DEFROSTER NOZZLE .................................... .169
RH AND LH SIDE DEMISTER DUCT .............. .169
RH AND LH VENTILATOR DUCT .................... .169
CENTER VENTILATOR DUCT ........................ .169
FLOOR DUCT .................................................. .169
REAR OVERHEAD DUCTS ............................. .170
REAR FLOOR DUCT ....................................... .170
GRILLES .......................................................... .170
REFRIGERANT LINES .......................................... .171
HFC-134a (R-134a) Service Procedure .............. .171
SETTING OF SERVICE TOOLS AND EQUIP-
MENT ............................................................... .171
Components ........................................................ .173
Removal and Installation for Compressor ........... .175
REMOVAL ........................................................ .175
INSTALLATION ................................................ .176
Removal and Installation for Compressor Clutch . 176 REMOVAL ........................................................ .176
INSPECTION ................................................... .177
INSTALLATION ................................................ .177
BREAK-IN OPERATION ................................... .179
Removal and Installation for Low-pressure Flexible
Hose .................................................................... .179
REMOVAL ........................................................ .179
INSTALLATION ................................................ .179
Removal and Installation for High-pressure Flexible
Hose .................................................................... .179
REMOVAL ........................................................ .179
INSTALLATION ................................................ .179
Removal and Installation for High-pressure Pipe . 179 REMOVAL ........................................................ .179
INSTALLATION ................................................ .179

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
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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-22
OIL
Revision: November 20092006 QX56
OILPFP:KLG00
Maintenance of Oil Quantity in CompressorEJS003X4
The oil in the compressor circulates through the system with the refrigerant. Add oil to compressor when
replacing any component or after a large refrigerant leakage has occurred. It is important to maintain the spec-
ified amount.
If oil quantity is not maintained properly, the following malfunctions may result:

Lack of oil: May lead to a seized compressor

Excessive oil: Inadequate cooling (thermal exchange interference)
OIL
Name: NISSAN A/C System Oil Type S (DH-PS) or equivalent
Part number: KLH00-PAGS0
CHECKING AND ADJUSTING
CAUTION:
If excessive oil leakage is noted, do not perform the oil return operation.
Start the engine and set the following conditions:
Test Condition

Engine speed: Idling to 1,200 rpm

A/C switch: On

Blower fan speed: MAX position

Temp. control: Optional [Set so that intake air temperature is 25° to 30 ° C (77 ° to 86 °F)]

Intake position: Recirculation ( )

Perform oil return operation for about ten minutes
Adjust the oil quantity according to the following table.
Oil Adjusting Procedure for Components Replacement Except Compressor
After replacing any of the following major components, add the correct amount of oil to the system.
Amount of oil to be added :

*1: If refrigerant leak is small, no addition of oil is needed.
Part replaced Oil to be added to system
Remarks
Amount of oil
m (US fl oz, Imp fl oz)
Front evaporator 75 (2.5, 2.6)—
Rear evaporator 75 (2.5, 2.6)—
Condenser 75 (2.5, 2.6)—
Liquid tank 5 (0.2, 0.2)Add if compressor is not replaced.
In case of refrigerant leak 30 (1.0, 1.1)
Large leak
— Small leak *1

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-28
AIR CONDITIONER CONTROL
Revision: November 20092006 QX56
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 maintained at the set temperature selected by the oper-
ator.

When pressing AUTO switch, air inlet, air outlet, blower speed, and discharge air temperature are auto-
matically controlled.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (DRIVER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE CONTROL) (PASSENGER SIDE)
Increases or decreases the set temperature.
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL) (REAR)
Increases or decreases the set temperature. The mode also changes from foot at full hot setting, to foot/vent
mid-range (warm) setting, and then to panel on full cold setting.
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 turned 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.
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 (FRONT)
Controls the air discharge outlets.
FRONT BLOWER CONTROL DIAL
Manually control the blower speed. Seven speeds are available for manual control (as shown on the display
screen).

AIR CONDITIONER CONTROLATC-29
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Rear Air Control
TEMPERATURE CONTROL DIAL (TEMPERATURE AND MODE CONTROL)
The temperature increases or decreases the set temperature. The mode also changes from foot at full hot set-
ting, to foot/vent at mid-range (warm) setting, and then to vent at full cold setting.
REAR BLOWER CONTROL DIAL
When the rear blower switch (front) is in the OFF position, the rear blower motor cannot operate.
When the rear blower switch (front) is in position (1-4), both the front and rear blower switch can control the
rear blower motor speed.
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