2004 INFINITI QX56 Engine cooling system

-1QUICK REFERENCE INDEX AGENERAL INFORMATIONGIGeneral InformationBENGINEEMEngine MechanicalLUEngine Lubrication SystemCOEngine Cooling SystemECEngine Control SystemFLFuel SystemEXExhaust SystemACCAccelerator Control SystemCTRANSMISSION/
TRANSAXLEATAutomatic TransmissionDDRIVELINE/AXLETFTransferPRPropeller ShaftFFDFront Final DriveRFDRear Final DriveFAXFront AxleRAXRear AxleESUSPENSIONFSUFront SuspensionRSURear SuspensionWTRoad Wheels & TiresFBRAKESBRBrake SystemPBParking Brake SystemBRCBrake Control SystemGSTEERINGPSPower Steering SystemHRESTRAINTSSBSeat BeltsSRSSupplemental Restraint System (SRS)IBODYBLBody, Lock & Security SystemGWGlasses, Window System & MirrorsRFRoofEIExterior & InteriorIPInstrument PanelSESeatAPAdjustable PedalsJAIR CONDITIONERATCAutomatic Air ConditionerKELECTRICALSCStarting & Charging SystemLTLighting SystemDIDriver Information SystemWWWiper, Washer & HornBCSBody Control SystemLANLAN SystemAVAudio Visual, Navigation & Telephone SystemACSAuto Cruise Control SystemPGPower Supply, Ground & Circuit ElementsLMAINTENANCEMAMaintenanceMINDEXIDXAlphabetical IndexEdition: February 2004
Revision: August 2007BDACEFGHIJKLM

2004
QUICK REFERENCE CHART: QX56

Disc Brake - Repair LimitsELS000ZU
Unit: mm (in)
Brake PedalELS000ZV
Unit: mm (in)
Refill CapacitiesELS000YO
Brake model CLZ31VC (Front) AD14VE (Rear)
Brake PadStandard thickness (new) 11.88 (0.468) 12.13 (0.478)
Repair limit thickness 1.0 (0.039) 1.0 (0.039)
Disc rotor Standard thickness (new) 26.0 (1.024) 14.0 (0.551)
Repair limit thickness 24.5 (0.965) 12.0 (0.472)
Maximum uneven wear (measured at 8 positions) 0.015 (0.0006) 0.015 (0.0006)
Runout limit (with it attached to the vehicle) 0.04 (0.0016) 0.05 (0.0020)
Brake pedal height (from dash lower panel top surface) 182.3
− 192.3 (7.18 − 7.57)
Depressed pedal height [under a force of 490 N (50 kg, 110 lb) with engine running] More than 90.3 (3.55)
Clearance between stopper rubber and the threaded end of stop lamp switch 0.74 − 1.96 (0.029 − 0.077)
Pedal play 3 − 11 (0.12 − 0.43)
Description Capacity (Approximate)
Metric US measure Imp measure
Fuel 105.8 28 gal 23 1/4 gal
Engine oil
Drain and refill With oil filter change
6.2 6 1/2 qt 5 1/2 qt
Without oil filter change 5.9 6 1/4 qt 5 1/4 qt
Dry engine (engine overhaul) 7.6 8 qt 6 3/4 qt
Cooling system With reservoir at MAX level 14.4 3 3/4 gal 3 1/8 gal
Automatic transmission fluid (ATF) 10.6 11 1/4 qt 9 3/8 qt
Rear final drive oil 1.75 3 3/4 pt 3 1/8 pt
Transfer fluid 3.0 3 1/8 qt 2 5/8 qt
Front final drive oil 1.6 3 3/8 pt 2 7/8 pt
Power steering fluid (PSF) 1.0 1 1/8 qt 7/8 qt
Windshield washer fluid 4.5 1 1/4 gal 1 gal
Air conditioning system refrigerant 1.08 ± 0.05 kg 2.38 ± 0.11 lb 2.38 ± 0.11 lb
Air conditioning system lubricants 290 m9.8 fl oz 10.2 fl oz

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-22
LUBRICANT
Revision: August 20072004 QX56
LUBRICANTPFP:KLG00
Maintenance of Lubricant Quantity in CompressorEJS002BV
The lubricant in the compressor circulates through the system with the refrigerant. Add lubricant to compres-
sor when replacing any component or after a large refrigerant leakage has occurred. It is important to maintain
the specified amount.
If lubricant quantity is not maintained properly, the following malfunctions may result:

Lack of lubricant: May lead to a seized compressor

Excessive lubricant: Inadequate cooling (thermal exchange interference)
LUBRICANT
Name: NISSAN A/C System Lubricant Type S (DH-PS)
Part number: KLH00-PAGS0
CHECKING AND ADJUSTING
CAUTION:
If excessive lubricant leakage is noted, do not perform the lubricant return operation.
Start the engine and set the following conditions:
test condition

Engine speed: Idling to 1,200 rpm

A/C switch: On

Blower 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 lubricant return operation for about ten minutes
Adjust the lubricant quantity according to the following table.
Lubricant Adjusting Procedure for Components Replacement Except Compressor
After replacing any of the following major components, add the correct amount of lubricant to the system.
Amount of Lubricant to be Added
*1: If refrigerant leak is small, no addition of lubricant is needed.
Lubricant Adjustment Procedure for Compressor Replacement
1. Before connecting recovery/recycling equipment to vehicle, check recovery/recycling equipment gauges.
No refrigerant pressure should be displayed. If NG, recover refrigerant from equipment lines.
2. Connect recovery/recycling equipment to vehicle. Confirm refrigerant purity in supply tank using recovery/
recycling equipment and refrigerant identifier. If NG, refer to AT C - 5 , "
Contaminated Refrigerant" .
3. Confirm refrigerant purity in vehicle A/C system using recovery/recycling equipment and refrigerant identi-
fier. If NG, refer to AT C - 5 , "
Contaminated Refrigerant" .
4. Discharge refrigerant into the refrigerant recovery/recycling equipment. Measure lubricant discharged into
the recovery/recycling equipment.
5. Drain the lubricant from the “old” (removed) compressor into a graduated container and recover the
amount of lubricant drained.
6. Drain the lubricant from the “new” compressor into a separate, clean container.
Part replacedLubricant to be added to system
Remarks
Amount of lubricant
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 leak30 (1.0, 1.1) Large leak
— Small leak *1

TROUBLE DIAGNOSIS
ATC-59
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AT C
Revision: August 20072004 QX56
Operational Check (Rear)EJS002CC
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear fan switch (front) clockwise to "1". The rear blower
should operate on low speed.
2. Turn the rear fan switch (front) clockwise again to switch position
"2", "3", and "4" until all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for AT C - 9 0 , "
Rear Blower
Motor Circuit" .
If OK, continue with next check.
CHECKING TEMPERATURE DECREASE
1. Rotate rear temperature/mode dial (front) fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets (headliner
outlets).
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 0 , "
Insufficient Cooling" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.
CHECKING TEMPERATURE INCREASE
1. Rotate rear temperature/mode dial (front) clockwise.
2. Check for hot air at appropriate discharge air outlets (floor out-
lets).
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 7 , "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.Conditions : Engine running and at normal operating temperature
WJIA0838E
WJIA0626E
WJIA0627E

ATC-114
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
TROUBLE DIAGNOSES FOR UNUSUAL PRESSURE
Whenever system′s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to preceding table (Ambient air tem-
perature-to-operating pressure table).
Both High- and Low-pressure Sides are Too High
High-pressure Side is Too High and Low-pressure Side is Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.Pressure is reduced soon
after water is splashed on
condenser.Excessive refrigerant charge
in refrigeration cycleReduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance
↓
1. Condenser fins are clogged.
2. Improper fan rotation of
cooling fan

Clean condenser.

Check and repair cooling fan
as necessary.

Low-pressure pipe is not
cold.

When compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2 , 28 psi). It then
decreases gradually there-
after.Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure
decreases too slowly.)
↓
Air in refrigeration cycleEvacuate and recharge sys-
tem.
Engine tends to overheat.Engine cooling systems mal-
function.Check and repair engine cool-
ing system.

An area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.

Plates are sometimes cov-
ered with frost.

Excessive liquid refrigerant
on low-pressure side

Excessive refrigerant dis-
charge flow

Expansion valve is open a
little compared with the
specification.
↓
Improper expansion valve
adjustmentReplace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high and
low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts
located between compressor
and condenser are clogged or
crushed.

Check and repair or replace
malfunctioning parts.

Check lubricant for contami-
nation.
AC360A

TROUBLE DIAGNOSIS
ATC-121
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Revision: August 20072004 QX56
Memory FunctionEJ S00 2CQ
SYMPTOM: Memory function does not operate.
INSPECTION FLOW
Water Valve CircuitEJS002CR
COMPONENT DESCRIPTION
Water Valve
The water valve cuts the flow of engine coolant to the front and rear
heater cores to allow for maximum cooling during A/C operation. It is
controlled by the front air control through the water valve relay.
*1ATC-60, "Power Supply and Ground
Circuit for Front Air Control"
*2AT C - 5 6 , "Operational Check (Front)"*3AT C - 5 3 , "A/C System Self-diagnosis
Function"
WJIA0797E
WJIA1015E

HEATER & COOLING UNIT ASSEMBLY
ATC-145
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Revision: August 20072004 QX56
Rear A/C
Removal and InstallationEJS002D5
FRONT HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Discharge the refrigerant from the A/C system. Refer to ATC-162, "Discharging Refrigerant" .
2. Drain the coolant from the engine cooling system. Refer to MA-12, "
DRAINING ENGINE COOLANT" .
3. Remove the cowl top extension. Refer to EI-18, "
Removal and Installation" .
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.