2004 INFINITI QX56 clutch

ATC-2Revision: August 20072004 QX56 TROUBLE DIAGNOSIS ............................................ 33
CONSULT-II Function (BCM) .................................. 33
CONSULT-II BASIC OPERATION ....................... 33
DATA MONITOR .................................................. 34
How to Perform Trouble Diagnosis for Quick and
Accurate Repair ...................................................... 35
WORK FLOW ...................................................... 35
SYMPTOM TABLE .............................................. 35
Component Parts and Harness Connector Location ... 37
ENGINE COMPARTMENT .................................. 37
FRONT PASSENGER COMPARTMENT ............ 38
REAR PASSENGER COMPARTMENT ............... 39
Schematic ............................................................... 40
Wiring Diagram — A/C,A — ................................... 41
Front Air Control Terminals and Reference Value ... 51
PIN CONNECTOR TERMINAL LAYOUT ............ 51
TERMINALS AND REFERENCE VALUE FOR
FRONT AIR CONTROL ....................................... 51
A/C System Self-diagnosis Function ...................... 53
DESCRIPTION .................................................... 53
Operational Check (Front) ...................................... 56
CHECKING MEMORY FUNCTION ..................... 56
CHECKING BLOWER ......................................... 56
CHECKING DISCHARGE AIR ............................ 57
CHECKING RECIRCULATION ............................ 57
CHECKING TEMPERATURE DECREASE ......... 57
CHECKING TEMPERATURE INCREASE .......... 58
CHECK A/C SWITCH .......................................... 58
CHECKING AUTO MODE ................................... 58
Operational Check (Rear) ....................................... 59
CHECKING BLOWER ......................................... 59
CHECKING TEMPERATURE DECREASE ......... 59
CHECKING TEMPERATURE INCREASE .......... 59
Power Supply and Ground Circuit for Front Air Con-
trol ........................................................................... 60
INSPECTION FLOW ........................................... 60
COMPONENT DESCRIPTION ............................ 61
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM ... 61
Mode Door Motor Circuit ........................................ 63
INSPECTION FLOW ........................................... 63
SYSTEM DESCRIPTION .................................... 64
COMPONENT DESCRIPTION ............................ 65
DIAGNOSTIC PROCEDURE FOR MODE
DOOR MOTOR ................................................... 65
Air Mix Door Motor Circuit ...................................... 67
INSPECTION FLOW ........................................... 67
SYSTEM DESCRIPTION .................................... 68
COMPONENT DESCRIPTION ............................ 69
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (DRIVER) ................................... 69
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER) .......................... 71
DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (REAR) ...................................... 73
Intake Door Motor Circuit ........................................ 76
INSPECTION FLOW ........................................... 76
SYSTEM DESCRIPTION .................................... 77
COMPONENT DESCRIPTION ............................ 78
DIAGNOSTIC PROCEDURE FOR INTAKE DOOR MOTOR ....................................................78
Defroster Door Motor Circuit ...................................79
SYMPTOM: ..........................................................79
INSPECTION FLOW ............................................79
SYSTEM DESCRIPTION .....................................80
COMPONENT DESCRIPTION ............................80
DIAGNOSTIC PROCEDURE FOR
DEFROSTER DOOR MOTOR .............................81
Front Blower Motor Circuit ......................................83
INSPECTION FLOW ............................................83
SYSTEM DESCRIPTION .....................................84
COMPONENT DESCRIPTION ............................85
DIAGNOSTIC PROCEDURE FOR BLOWER
MOTOR ................................................................85
COMPONENT INSPECTION ...............................89
Rear Blower Motor Circuit .......................................90
INSPECTION FLOW ............................................90
SYSTEM DESCRIPTION .....................................91
DIAGNOSTIC PROCEDURE FOR REAR
BLOWER MOTOR ...............................................91
COMPONENT INSPECTION ...............................99
Rear Air Control Circuit ......................................... 101
INSPECTION FLOW .......................................... 101
SYSTEM DESCRIPTION ................................... 102
DIAGNOSTIC PROCEDURE FOR REAR AIR
CONTROL ......................................................... 102
Magnet Clutch Circuit ............................................ 104
INSPECTION FLOW .......................................... 104
SYSTEM DESCRIPTION ................................... 105
DIAGNOSTIC PROCEDURE FOR MAGNET
CLUTCH ............................................................ 105
Insufficient Cooling ................................................110
INSPECTION FLOW ..........................................110
PERFORMANCE TEST DIAGNOSES .............. 111
PERFORMANCE CHART ..................................113
TROUBLE DIAGNOSES FOR UNUSUAL PRES-
SURE .................................................................114
Insufficient Heating ...............................................117
INSPECTION FLOW ..........................................117
Noise .....................................................................118
INSPECTION FLOW ..........................................118
Self-diagnosis ....................................................... 120
INSPECTION FLOW .......................................... 120
Memory Function .................................................. 121
INSPECTION FLOW .......................................... 121
Water Valve Circuit ................................................ 121
COMPONENT DESCRIPTION .......................... 121
DIAGNOSTIC PROCEDURE FOR WATER
VALVE ................................................................ 122
COMPONENT INSPECTION ............................. 124
Ambient Sensor Circuit ......................................... 125
COMPONENT DESCRIPTION .......................... 125
AMBIENT TEMPERATURE INPUT PROCESS . 125
DIAGNOSTIC PROCEDURE FOR AMBIENT
SENSOR ............................................................ 125
COMPONENT INSPECTION ............................. 127
In-vehicle Sensor Circuit ....................................... 128
COMPONENT DESCRIPTION .......................... 128
DIAGNOSTIC PROCEDURE FOR IN-VEHICLE

ATC-3
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Revision: August 20072004 QX56 SENSOR ........................................................... 129
COMPONENT INSPECTION ............................ 131
Optical Sensor Circuit .......................................... 131
COMPONENT DESCRIPTION ......................... 131
OPTICAL INPUT PROCESS ............................ 131
DIAGNOSTIC PROCEDURE FOR OPTICAL
SENSOR ........................................................... 132
Intake Sensor Circuit ............................................ 133
COMPONENT DESCRIPTION ......................... 133
DIAGNOSTIC PROCEDURE FOR INTAKE SEN-
SOR .................................................................. 133
COMPONENT INSPECTION ............................ 134
CONTROL UNIT ..................................................... 135
Removal and Installation ...................................... 135
FRONT AIR CONTROL .................................... 135
REAR AIR CONTROL ....................................... 135
AMBIENT SENSOR ................................................ 136
Removal and Installation ...................................... 136
REMOVAL ......................................................... 136
INSTALLATION ................................................. 136
IN-VEHICLE SENSOR ............................................ 137
Removal and Installation ...................................... 137
REMOVAL ......................................................... 137
INSTALLATION ................................................. 137
OPTICAL SENSOR ................................................ 138
Removal and Installation ...................................... 138
INTAKE SENSOR ................................................... 139
Removal and Installation ...................................... 139
REMOVAL ......................................................... 139
INSTALLATION ................................................. 139
BLOWER MOTOR .................................................. 140
Components ......................................................... 140
Removal and Installation ...................................... 140
FRONT BLOWER MOTOR ............................... 140
REAR BLOWER MOTOR ................................. 141
IN-CABIN MICROFILTER ....................................... 142
Removal and Installation ...................................... 142
FUNCTION ........................................................ 142
REPLACEMENT TIMING .................................. 142
REPLACEMENT PROCEDURE ....................... 142
HEATER & COOLING UNIT ASSEMBLY .............. 144
Components ......................................................... 144
Removal and Installation ...................................... 145
FRONT HEATER AND COOLING UNIT ASSEM-
BLY .................................................................... 145
REAR HEATER AND COOLING UNIT ASSEM-
BLY .................................................................... 146
HEATER CORE ...................................................... 147
Components ......................................................... 147
Removal and Installation ...................................... 148
FRONT HEATER CORE ................................... 148
REAR HEATER CORE ..................................... 149
DEFROSTER DOOR MOTOR ................................ 150
Removal and Installation ...................................... 150
REMOVAL ......................................................... 150
INSTALLATION ................................................. 150INTAKE DOOR MOTOR .........................................151
Removal and Installation ......................................151
REMOVAL .........................................................151
INSTALLATION .................................................151
MODE DOOR MOTOR ............................................152
Removal and Installation ......................................152
REMOVAL .........................................................152
INSTALLATION .................................................152
AIR MIX DOOR MOTOR .........................................153
Components .........................................................153
Removal and Installation ......................................153
FRONT AIR MIX DOOR MOTOR (DRIVER) .....153
FRONT AIR MIX DOOR MOTOR (PASSENGER) .154
REAR AIR MIX DOOR MOTOR ........................154
VARIABLE BLOWER CONTROL ...........................155
Removal and Installation ......................................155
REMOVAL .........................................................155
INSTALLATION .................................................155
REAR BLOWER MOTOR RESISTOR ....................156
Removal and Installation ......................................156
REMOVAL .........................................................156
INSTALLATION .................................................156
DUCTS AND GRILLES ...........................................157
Components .........................................................157
Removal and Installation ......................................160
CENTER CONSOLE HEAT DUCT AND REAR
FINISHER ASSEMBLY GRILLE ........................160
DEFROSTER NOZZLE .....................................160
RH AND LH SIDE DEMISTER DUCT ...............160
RH AND LH VENTILATOR DUCT .....................160
CENTER VENTILATOR DUCT .........................160
FLOOR DUCT ...................................................160
REAR OVERHEAD DUCTS ..............................160
REAR FLOOR DUCT ........................................161
GRILLES ...........................................................161
REFRIGERANT LINES ...........................................162
HFC-134a (R-134a) Service Procedure ...............162
SETTING OF SERVICE TOOLS AND EQUIP-
MENT ................................................................162
Components .........................................................164
Removal and Installation for Compressor ............166
REMOVAL .........................................................166
INSTALLATION .................................................167
Removal and Installation for Compressor Clutch . 167
REMOVAL .........................................................167
INSPECTION ....................................................168
INSTALLATION .................................................168
BREAK-IN OPERATION ....................................170
Removal and Installation for Low-pressure Flexible
Hose .....................................................................170
REMOVAL .........................................................170
INSTALLATION .................................................170
Removal and Installation for High-pressure Flexible
Hose .....................................................................170
REMOVAL .........................................................170
INSTALLATION .................................................170
Removal and Installation for High-pressure Pipe . 170
REMOVAL .........................................................170
INSTALLATION .................................................171

PRECAUTIONS
ATC-11
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After connecting line, conduct leak test and make sure that there is no leakage from connections.
When the gas leaking point is found, disconnect that line and replace the O-ring. Then tighten con-
nections of seal seat to the specified torque.
Precautions for Servicing CompressorEJS002BM

Plug all openings to prevent moisture and foreign matter from entering.

When the compressor is removed, store it in the same position as it is when mounted on the car.

When replacing or repairing compressor, follow “Maintenance of Lubricant Quantity in Compres-
sor” exactly. Refer to ATC-22, "
Maintenance of Lubricant Quantity in Compressor" .

Keep friction surfaces between clutch and pulley clean. If the surface is contaminated with lubri-
cant, wipe it off by using a clean waste cloth moistened with thinner.

After compressor service operation, turn the compressor shaft by hand more than 5 turns in both
directions. This will equally distribute lubricant inside the compressor. After the compressor is
installed, let the engine idle and operate the compressor for 1 hour.

After replacing the compressor magnet clutch, apply voltage to the new one and check for normal
operation. Refer to ATC-167, "
Removal and Installation for Compressor Clutch"
Precautions for Service EquipmentEJS002BN
RECOVERY/RECYCLING EQUIPMENT
Follow the manufacturer's instructions for machine operation and machine maintenance. Never introduce any
refrigerant other than that specified into the machine.
ELECTRONIC LEAK DETECTOR
Follow the manufacturer's instructions for tester operation and tester maintenance.
RHA861F

PREPARATION
ATC-17
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Commercial Service ToolsEJS002BR
Tool nameDescription
(J-41810-NI)
Refrigerant identifier equipment-
(R-134a)For checking refrigerant purity and
system contamination
Power toolLoosening bolts and nuts
(J-44614)
Clutch disc holding toolClutch disc holding tool
RJIA0197E
PBIC0190E
WHA230

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).

AIR CONDITIONER CONTROL
ATC-25
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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

TROUBLE DIAGNOSIS
ATC-35
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How to Perform Trouble Diagnosis for Quick and Accurate RepairEJS002C5
WORK FLOW
SYMPTOM TABLE
*1ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)" .
SHA9 00 E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System.AT C - 6 0 , "
Power
Supply and
Ground Circuit for
Front Air Control"
A/C system display is malfunctioning. Go to "Navigation System".AV-61, "NAVIGA-
TION SYSTEM"
A/C system cannot be controlled. Go to Self-diagnosis Function.AT C - 5 3 , "
A/C Sys-
tem Self-diagno-
sis Function"
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor.AT C - 6 3 , "Mode
Door Motor Cir-
cuit"Mode door motor is malfunctioning.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor.ATC-67, "
Air Mix
Door Motor Cir-
cuit"Air mix door motor is malfunctioning.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor.ATC-76, "
Intake
Door Motor Cir-
cuit"Intake door motor is malfunctioning.
Defroster door motor is malfunctioning. Go to Trouble Diagnosis Procedure for Defroster Door Motor.AT C - 7 9 ,
"Defroster Door
Motor Circuit"
Front blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Front Blower Motor.AT C - 8 3 , "Front
Blower Motor Cir-
cuit"
Rear blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Rear Blower Motor.AT C - 9 0 , "Rear
Blower Motor Cir-
cuit"
Rear discharge air temperature and/or air
outlet does not change.Go to Trouble Diagnosis Procedure for Rear Air Control circuit.ATC-101, "Rear
Air Control Circuit"
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch.ATC-104, "Mag-
net Clutch Circuit"
Insufficient cooling Go to Trouble Diagnosis Procedure for Insufficient Cooling.AT C - 11 0 , "Insuffi-
cient Cooling"
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.AT C - 11 7 , "Insuffi-
cient Heating"
Noise Go to Trouble Diagnosis Procedure for Noise.ATC-118, "Noise"

TROUBLE DIAGNOSIS
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SELF-DIAGNOSIS CODE CHART
Code No. Reference page
02 EE changed by calibrationATC-135, "
FRONT AIR CONTROL"
03 Battery voltage out of rangeSC-4, "BATTERY"
04 Mode switch circuit open or shortATC-135, "FRONT AIR CONTROL"
05 Blower motor malfunctionAT C - 8 3 , "Front Blower Motor Circuit"
12 Air mix door motor (Passenger) circuit malfunctionAT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
20 BCM not responding to A/C requestATC-104, "Magnet Clutch Circuit"
21 BCM not responding to rear defroster requestGW-78, "REAR WINDOW DEFOGGER"
22 Air mix door motor (Driver) circuit malfunctionAT C - 6 9 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
30 In-vehicle sensor circuit out of range (low)
ATC-128, "In-vehicle Sensor Circuit"31 In-vehicle sensor circuit out of range (high)
34 Air mix door motor (Driver) PBR circuit malfunctionAT C - 6 9 , "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
36Air mix door motor (Passenger) PBR circuit malfunc-
tionAT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
38 Air mix door motor (rear) circuit malfunctionAT C - 7 3 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (REAR)"
40 Ambient sensor circuit short
ATC-125, "Ambient Sensor Circuit"41 Ambient sensor circuit open
44 In-vehicle sensor motor circuit open
ATC-128, "
In-vehicle Sensor Circuit"46 In-vehicle sensor motor circuit short
50 Optical sensor (Driver) circuit open or short
ATC-131, "
Optical Sensor Circuit"52 Optical sensor (Passenger) circuit open or short
56 Intake sensor circuit short
ATC-133, "
Intake Sensor Circuit"57 Intake sensor circuit open
62 Defroster door motor circuit malfunctionAT C - 7 9 , "
Defroster Door Motor Circuit"
72 Intake door motor circuit malfunctionAT C - 7 6 , "Intake Door Motor Circuit"
80 CAN bus malfunction
LAN-5, "CAN COMMUNICATION"81 CAN BCM message missing
82 Intake door motor circuit malfunctionAT C - 7 6 , "
Intake Door Motor Circuit"
90 Stuck buttonATC-135, "FRONT AIR CONTROL"
92 Mode door motor circuit malfunctionAT C - 6 3 , "Mode Door Motor Circuit"