heating INFINITI QX56 2004 Factory Service Manual

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

TROUBLE DIAGNOSIS
ATC-35
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AT C
Revision: August 20072004 QX56
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"

ATC-58
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
CHECKING TEMPERATURE INCREASE
1. Rotate temperature dial clockwise (driver or passenger) until
32°C (90°F) is displayed.
2. Check for hot air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for ATC-117, "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to ATC-69,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)" or AT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue with next check.
CHECK A/C SWITCH
1. Press A/C switch.
2. A/C switch indicator will turn ON.

Confirm that the compressor clutch engages (sound or visual
inspection).
If NG, go to trouble diagnosis procedure for ATC-104, "
Magnet
Clutch Circuit" .
If OK, continue with next check.
CHECKING AUTO MODE
1. Press AUTO switch.
2. Display should indicate AUTO.

If ambient temperature is warm, and selected temperature is
cool, confirm that the compressor clutch engages (sound or
visual inspection). (Discharge air and blower speed will
depend on ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for ATC-60, "
Power Supply
and Ground Circuit for Front Air Control" , then if necessary, trouble
diagnosis procedure for ATC-104, "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in AT C - 3 5 , "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" and perform tests as out-
lined to simulate driving conditions environment. If symptom appears. Refer to ATC-35, "
How to Perform Trou-
ble Diagnosis for Quick and Accurate Repair" , AT C - 3 5 , "SYMPTOM TABLE" and perform applicable trouble
diagnosis procedures.
WJIA0409E
WJIA0410E
WJIA0411E

TROUBLE DIAGNOSIS
ATC-59
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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

TROUBLE DIAGNOSIS
ATC-117
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Revision: August 20072004 QX56
Insufficient HeatingEJS002CN
SYMPTOM: Insufficient heating
INSPECTION FLOW
*1 .ATC-56, "Operational Check
(Front)" or AT C - 5 9 , "Operational
Check (Rear)"
*2AT C - 6 7 , "Air Mix Door Motor Circuit"*3AT C - 5 3 , "A/C System Self-diagno-
sis Function"
*4AT C - 5 3 , "A/C System Self-diagnosis
Function"
*5AT C - 8 3 , "Front Blower Motor Circuit"*6EC-165, "DTC P0117, P0118 ECT
SENSOR"
*7MA-12, "Changing Engine Coolant"*8CO-8, "CHECKING RESERVOIR
CAP"
*9ATC-121, "Water Valve Circuit"
*10CO-4, "OVERHEATING CAUSE
ANALYSIS"
WJIA0812E

BL-192
BODY REPAIR
Revision: August 20072004 QX56
Precautions in Repairing High Strength SteelEIS002UA
High strength steel is used for body panels in order to reduce vehicle weight.
Accordingly, precautions in repairing automotive bodies made of high strength steel are described below:
HIGH STRENGTH STEEL (HSS) USED IN NISSAN VEHICLES
SP130 is the most commonly used HSS.
SP150 HSS is used only on parts that require much more strength.
Read the following precautions when repairing HSS:
1. Additional points to consider

The repair of reinforcements (such as side members) by heat-
ing is not recommended since it may weaken the component.
When heating is unavoidable, do not heat HSS parts above
550°C (1,022°F).
Verify heating temperature with a thermometer.
(Crayon-type and other similar type thermometer are appro-
priate.)

When straightening body panels, use caution in pulling any
HSS panel. Because HSS is very strong, pulling may cause
deformation in adjacent portions of the body. In this case,
increase the number of measuring points, and carefully pull
the HSS panel.

When cutting HSS panels, avoid gas (torch) cutting if possi-
ble. Instead, use a saw to avoid weakening surrounding areas
due to heat. If gas (torch) cutting is unavoidable, allow a mini-
mum margin of 50 mm (1.97in).
Tensile strength Nissan/Infiniti designation Major applicable parts
373 N/mm
2
(38kg/mm2 ,54klb/sq in)SP130

Front inner pillar upper

Front pillar hinge brace

Outer front pillar reinforcement

Other reinforcements
785-981 N/mm
2
(80-100kg/mm2
114-142klb/sq in)SP150

Outer sill reinforcement

Main back pillar
PIIA0115E
PIIA0116E
PIIA0117E

CO-1
ENGINE COOLING SYSTEM
B ENGINE
CONTENTS
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SECTION CO
A
CO
Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 2
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 2
PREPARATION ........................................................... 3
Special Service Tools ............................................... 3
Commercial Service Tools ........................................ 3
OVERHEATING CAUSE ANALYSIS .......................... 4
Troubleshooting Chart .............................................. 4
COOLING SYSTEM .................................................... 6
Cooling Circuit .......................................................... 6
System Drawing ....................................................... 7
ENGINE COOLANT .................................................... 8
Inspection ................................................................. 8
LEVEL CHECK ..................................................... 8
CHECKING COOLING SYSTEM FOR LEAKS ..... 8
CHECKING RESERVOIR CAP ............................. 8
CHECKING RADIATOR CAP ................................ 8
Changing Engine Coolant ........................................ 8
DRAINING ENGINE COOLANT ........................... 8
REFILLING ENGINE COOLANT .......................... 9
FLUSHING COOLING SYSTEM ........................... 9
RADIATOR ................................................................ 10
Removal and Installation ........................................ 10
REMOVAL ........................................................... 10
INSTALLATION ................................................... 12
INSPECTION AFTER INSTALLATION ............... 12
Checking Radiator .................................................. 12ENGINE COOLING FAN ........................................... 13
Removal and Installation (Crankshaft Driven Type) ... 13
REMOVAL ........................................................... 13
INSPECTION AFTER REMOVAL ....................... 13
INSTALLATION ................................................... 13
INSPECTION AFTER INSTALLATION ................ 13
Removal and Installation (Motor Driven Type) ....... 14
REMOVAL ........................................................... 14
INSTALLATION ................................................... 14
WATER PUMP .......................................................... 15
Removal and Installation ........................................ 15
REMOVAL ........................................................... 15
INSPECTION AFTER REMOVAL ....................... 15
INSTALLATION ................................................... 15
INSPECTION AFTER INSTALLATION ................ 16
THERMOSTAT AND WATER PIPING ...................... 17
Removal and Installation ........................................ 17
REMOVAL ........................................................... 17
INSPECTION AFTER REMOVAL ....................... 18
INSTALLATION ................................................... 18
INSPECTION AFTER INSTALLATION ................ 18
SERVICE DATA AND SPECIFICATIONS (SDS) ...... 19
Standard and Limit .................................................. 19
ENGINE COOLANT CAPACITY (APPROXI-
MATE) .................................................................. 19
THERMOSTAT .................................................... 19
RADIATOR .......................................................... 19

CO-4Revision: August 2007
OVERHEATING CAUSE ANALYSIS
2004 QX56
OVERHEATING CAUSE ANALYSISPFP:00012
Troubleshooting ChartEBS00I4T
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
— Thermostat stuck closed —
Damaged finsDust contamination or
paper clogging
Physical damage
Clogged radiator cooling
tubeExcess foreign material
(rust, dirt, sand, etc.)
Water cut valve malfunctionExcess foreign material
(rust, dirt, sand, etc.), phys-
ical damage
Reduced air flowCooling fan does not oper-
ate
Fan assembly — High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud — — —
Improper engine coolant
mixture ratio—— —
Poor engine coolant quality — Engine coolant density —
Insufficient engine coolantEngine coolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into
cooling systemCylinder head deterioration
Cylinder head gasket dete-
rioration

OVERHEATING CAUSE ANALYSIS
CO-5
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Revision: August 20072004 QX56
Except cool-
ing system
parts mal-
function— Overload on engineAbusive drivingHigh engine rpm under no
load
Driving in low gear for
extended time
Driving at extremely high
speed
Powertrain system mal-
function
— Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flowBlocked bumper —
— Blocked radiator grilleInstalled car brassiere
Mud contamination or
paper clogging
Blocked radiator —
Blocked condenser
Blocked air flow
Installed large fog lamp Symptom Check items

CO-18Revision: August 2007
THERMOSTAT AND WATER PIPING
2004 QX56
CAUTION:
Perform when the engine is cold.
2. Remove air duct and resonator assembly. Refer to EM-14, "
REMOVAL" .
3. Remove engine room cover using power tools.
4. Disconnect heater hose (heater core side).
5. Remove heater hose bracket.
6. Disconnect the water cut valve connector.
7. Remove the water cut valve
INSPECTION AFTER REMOVAL

Place a thread so that it is caught in the valve of the thermostat.
Immerse fully in a container filled with water. Heat while stirring.

The valve opening temperature is the temperature at which the
valve opens and falls from the thread.

Continue heating. Check the full-open lift amount.

After checking the full-open lift amount, lower the water temper-
ature and check the valve closing temperature.
Standard values:
INSTALLATION
Installation is in the reverse order of removal.
Installation of Thermostat

Install the thermostat with the whole circumference of each
flange part fit securely inside the rubber ring as shown.

Install the thermostat with the jiggle valve facing upwards.
Installation of Water Outlet Pipe and Heater Pipe
First apply a neutral detergent to the O-rings, then quickly insert the insertion parts of the water outlet pipe and
heater pipe into the installation holes.
INSPECTION AFTER INSTALLATION

Check for leaks of the engine coolant. Refer to CO-8, "CHECKING COOLING SYSTEM FOR LEAKS" .

Start and warm up the engine. Visually make sure that there is no leaks of the engine coolant.
SL C2 52 B
Thermostat
Valve opening temperature 80 - 84°C (176 - 183° F)
Full-open lift amount More than 10 mm/ 95°C (0.39 in/ 203°F)
Valve closing temperature 77°C (171°F) or higher
KBIA2502E