heating INFINITI QX56 2007 Factory Service Manual

ATC-1
AIR CONDITIONER
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SECTION AT C
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AT C
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CONTENTS
AUTOMATIC AIR CONDITIONER
SERVICE INFORMATION .. ..........................3
PRECAUTIONS .............................................. .....3
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ............................................................. ......
3
Precaution for Working with HFC-134a (R-134a) ......3
Contaminated Refrigerant .........................................3
General Refrigerant Precaution ................................4
Precaution for Leak Detection Dye ...........................4
A/C Identification Label .............................................4
Precaution for Refrigerant Connection ......................4
Precaution for Service of Compressor ................ ......9
Precaution for Service Equipment ....................... ......9
PREPARATION ..................................................12
Special Service Tool ........................................... ....12
HFC-134a (R-134a) Service Tool and Equipment ....12
Commercial Service Tool ........................................14
REFRIGERATION SYSTEM ..............................16
Refrigerant Cycle ................................................ ....16
Refrigerant System Protection ................................16
Component Part Location ................................... ....17
OIL ......................................................................20
Maintenance of Oil Quantity in Compressor ....... ....20
AIR CONDITIONER CONTROL .........................22
Description .......................................................... ....22
Operation ................................................................22
Description of Control System .................................23
Control Operation ....................................................24
Discharge Air Flow ..................................................26
System Description (Front) .....................................27
System Description (Rear) .................................. ....28
CAN Communication System Description ...............29
TROUBLE DIAGNOSIS .....................................30
CONSULT-II Function (HVAC) ............................ ....30
CONSULT-II Function (BCM) ..................................31
How to Perform Trouble Diagnosis for Quick and
Accurate Repair ................................................... ....
32
Component Parts and Harness Connector Loca-
tion ...........................................................................
32
Schematic ................................................................36
Wiring Diagram - A/C,A - .........................................37
Front Air Control Terminal and Reference Value ....47
A/C System Self-Diagnosis Function .......................48
Operational Check (Front) ................................... ....50
Operational Check (Rear) ........................................51
Power Supply and Ground Circuit for Front Air
Control ................................................................. ....
52
Mode Door Motor Circuit .........................................54
Air Mix Door Motor Circuit ................................... ....59
Intake Door Motor Circuit .........................................70
Defroster Door Motor Circuit ....................................74
Front Blower Motor Circuit .......................................78
Rear Blower Motor Circuit ................................... ....85
Rear Air Control Circuit ............................................93
Magnet Clutch Circuit ..............................................96
Insufficient Cooling ................................................100
Insufficient Heating ................................................108
Noise .....................................................................109
Self-Diagnosis .......................................................111
Memory Function ...................................................112
Water Valve Circuit ................................................113
Ambient Sensor Circuit ..........................................114
In-vehicle Sensor Circuit ........................................116
Optical Sensor Circuit ............................................119
Intake Sensor Circuit .............................................120
CONTROL UNIT ..............................................123
Removal and Installation .......................................123
AMBIENT SENSOR ........................................124
Removal and Installation .......................................124
IN-VEHICLE SENSOR ....................................125
Removal and Installation .......................................125
OPTICAL SENSOR .........................................126

ATC-32
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
How to Perform Trouble Diagnosis for Quick and Accurate Repair
INFOID:0000000003533243
WORK FLOW
SYMPTOM TABLE
Component Parts and Harness Connector LocationINFOID:0000000003533244
ENGINE COMPARTMENT
*1AT C - 5 0 , "Operational Check (Front)"
or AT C - 5 1 , "
Operational Check
(Rear)" .
SHA900E
Symptom Reference Page
A/C system does not come on. Go to Trouble Diagnosis Procedure for A/C System. AT C - 5 2
A/C system display is malfunctioning. Go to Navigation System. AV- 7 3
A/C system cannot be controlled. Go to Self-diagnosis Function.AT C - 4 8 , "
A/C Sys-
tem Self-Diagno-
sis Function"
Air outlet does not change.
Go to Trouble Diagnosis Procedure for Mode Door Motor. AT C - 5 4
Mode door motor is malfunctioning.
Discharge air temperature does not change.
Go to Trouble Diagnosis Procedure for Air Mix Door Motor. AT C - 5 9
Air mix door motor is malfunctioning.
Intake door does not change.
Go to Trouble Diagnosis Procedure for Intake Door Motor. AT C - 7 0
Intake door motor is malfunctioning.
Defroster door motor is malfunctioning. Go to Trouble Diagnosis Procedure for Defroster Door Motor. AT C - 7 4
Front blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Front Blower Motor.
AT C - 7 8
Rear blower motor operation is malfunction-
ing.Go to Trouble Diagnosis Procedure for Rear Blower Motor.
AT C - 8 5
Rear discharge air temperature and/or air
outlet does not change.Go to Trouble Diagnosis Procedure for Rear Air Control circuit.
AT C - 9 3
Magnet clutch does not engage. Go to Trouble Diagnosis Procedure for Magnet Clutch. AT C - 9 6
Insufficient cooling Go to Trouble Diagnosis Procedure for Insufficient Cooling.AT C - 1 0 0
Insufficient heating Go to Trouble Diagnosis Procedure for Insufficient Heating.AT C - 1 0 8
Noise Go to Trouble Diagnosis Procedure for Noise.AT C - 1 0 9
Self-diagnosis cannot be performed. Go to Trouble Diagnosis Procedure for Self-diagnosis. AT C - 111
Memory function does not operate. Go to Trouble Diagnosis Procedure for Memory Function.AT C - 11 2

TROUBLE DIAGNOSISATC-51
< SERVICE INFORMATION >
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1. Rotate temperature control dial (driver si de or passenger side) counterclockwise until 16 °C (60 °F) is dis-
played.
2. Check for cold air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operat ion. If OK, go to trouble diagnosis procedure for ATC-100,
"Insufficient Cooling" . If air mix door motor appears to be malfunctioning, go to ATC-59, "Air Mix Door Motor
Circuit" or ATC-59, "Air Mix Door Motor Circuit".
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Rotate temperature control dial clockw ise (driver side or passenger side) 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 operat ion. If OK, go to trouble diagnosis procedure for ATC-108,
"Insufficient Heating" . If air mix door motor appears to be malfunctioning, go to ATC-59, "Air Mix Door Motor
Circuit" or ATC-59, "Air Mix Door Motor Circuit".
If OK, continue with next check.
CHECK A/C SWITCH
1. Press A/C switch when AUTO switch is ON, or in manual mode.
2. A/C switch indicator will turn ON.
• Confirm that the compressor clutch engages (sound or visual inspection).
NOTE:
If current mode setting is DEF or D/F, compressor clutch may already be engaged.
If NG, go to trouble diagnosis procedure for ATC-96, "
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 temperat ure is cool, confirm that the compressor clutch
engages (sound or visual inspection). (Discharge air and blower speed will depend on ambient, in-vehi-
cle, and set temperatures.)
If NG, go to trouble diagnosis procedure for ATC-52, "
Power Supply and Ground Circuit for Front Air Control" ,
then if necessary, trouble diagnosis procedure for ATC-96, "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go to malfunction Simulation Tests in AT C -
32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair" and perform tests as outlined to simu-
late driving conditions environment . If symptom appears. Refer to ATC-32, "
How to Perform Trouble Diagnosis
for Quick and Accurate Repair", ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair"
and perform applicable trouble diagnosis procedures.
Operational Check (Rear)INFOID:0000000003533250
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear blower control dial to swit ch position "1". Blower should operate on low speed.
2. Turn the rear blower control dial counterclockwis e to switch position "2", "3", and "4" until all speeds are
checked.
3. Leave blower on MAX speed.
If NG, go to trouble diagnosis procedure for ATC-85, "
Rear Blower Motor Circuit" .
If OK, continue the check.
CHECKING TEMPERATURE DECREASE
1. Rotate temperature and mode dial fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets. Conditions : Engine running and at normal operating temperature

ATC-52
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
If NG, listen for sound of air mix door motor operation if OK, go to trouble diagnosis procedure for ATC-100,
"Insufficient Cooling" . If air mix door motor appears to be malfunctioning, go to ATC-59, "Air Mix Door Motor
Circuit".
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Rotate temperature and mode dial clockwise.
2. Check for hot air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operat ion. If OK, go to trouble diagnosis procedure for ATC-108,
"Insufficient Heating". If air mix door motor appears to be malfunctioning, go to ATC-59, "Air Mix Door Motor
Circuit" .
If OK, continue the check.
Power Supply and Ground Circu it for Front Air ControlINFOID:0000000003533251
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - AUTO MODE
1. Press AUTO switch.
2. Display should indicate AUTO. Confirm that the compressor clutch engages (sound or visual inspection).
(Discharge air and blower speed will depend on am bient, in-vehicle and set temperatures.)
Can a symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.PERFORM COMPLETE OPERATIONAL CHECK
Perform a complete operational check and check for any symptoms. Refer to ATC-50, "
Operational Check
(Front)".
Can a symptom be duplicated
YES >> Refer to ATC-32, "How to Perform Trouble Diagnosis for Quick and Accurate Repair".
NO >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.CHECK POWER AND GROUND CIRCUIT
Check main power supply and ground circuit. Refe r to "DIAGNOSTIC PROCEDURE FOR A/C SYSTEM".
OK or NG
OK >> System OK.
NO >> Replace front air control. Refer to ATC-123, "
Removal and Installation".
COMPONENT DESCRIPTION
Front Air Control
The front air control has a built-in microcomputer which processes
information sent from various sensors needed for air conditioner
operation. The air mix door motors, mode door motor, intake door
motor, defroster door motor, blower motor and compressor are then
controlled.
The front air control is unitized with control mechanisms. When the
various switches and temperature dials are operated, data is input to
the front air control.
Self-diagnostic functions are also built into the front air control to pro-
vide quick check of malfunctions in the auto air conditioner system.
WJIA0544E

ATC-108
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
Insufficient Heating
INFOID:0000000003533261
SYMPTOM: Insufficient heating
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING OPER ATIONAL CHECK - TEMPERATURE INCREASE
1. Press the AUTO switch.
2. Turn the temperature control dial (driver) clockwise until 32 ° C (90 ° F) is displayed.
3. Check for hot air at discharge air outlets.
Can this symptom be duplicated?
YES >> GO TO 2.
NO >> Perform complete system operational check. Refer to ATC-50, "
Operational Check (Front)" .
2.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 3.
3.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis. Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
OK or NG
OK >> GO TO 4.
NG >> Refer to ATC-48, "
A/C System Self-Diagnosis Function" .
4.CHECK ENGINE COOLING SYSTEM
1. Check for proper engine coolant level. Refer to CO-9, "
Inspection".
2. Check hoses for leaks or kinks.
3. Check radiator cap. Refer to CO-9, "
Inspection" .
4. Check for air in cooling system.
>> GO TO 5.
5.CHECK AIR MIX DOOR OPERATION
Check the operation of the air mix door.
OK or NG
Gauge indication Refrigerant cycle Probable cause Corrective action
Low-pressure side becomes nega-
tive. Liquid tank or front/rear side of
expansion valve′s pipe is frost-
ed or dewed. High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted. Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.
• If water is the cause, initially
cooling is okay. Then the wa-
ter freezes causing a block-
age. Drain water from
refrigerant or replace refrig-
erant.
• If due to foreign particles, re-
move expansion valve and
remove the particles with dry
and compressed air (not
shop air).
• If either of the above meth- ods cannot correct the mal-
function, replace expansion
valve.
• Replace liquid tank.
• Check oil for contamination.
AC362A

BODY REPAIR
BL-167
< SERVICE INFORMATION >
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Precaution in Repairing High Strength SteelINFOID:0000000003533012
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 appropri-
ate.)
LIIA1061E
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

CO-1
ENGINE
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SECTION CO
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CONTENTS
ENGINE COOLING SYSTEM
SERVICE INFORMATION ............................2
PRECAUTIONS ...................................................2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
2
Precaution for Liquid Gasket .....................................2
PREPARATION ...................................................4
Special Service Tool .................................................4
Commercial Service Tool ..........................................4
OVERHEATING CAUSE ANALYSIS ..................6
Troubleshooting Chart ...............................................6
COOLING SYSTEM ............................................8
Cooling Circuit ...........................................................8
Schematic .................................................................8
ENGINE COOLANT ............................................9
Inspection ..................................................................9
Changing Engine Coolant .........................................9
RADIATOR ........................................................13
Removal and Installation .........................................13
Checking Radiator ...................................................15
ENGINE COOLING FAN ...................................16
Removal and Installation (Crankshaft Driven
Type) .......................................................................
16
Removal and Installation (Motor Driven Type) ........17
WATER PUMP ..................................................18
Removal and Installation .........................................18
THERMOSTAT AND WATER PIPING ..............20
Removal and Installation .........................................20
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
22
Standard and Limit ..................................................22

CO-6
< SERVICE INFORMATION >
OVERHEATING CAUSE ANALYSIS
OVERHEATING CAUSE ANALYSIS
Troubleshooting ChartINFOID:0000000003531566
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
— Thermostat stuck closed —
Damaged finsDust contamination or pa-
per 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 cool-
ing systemCylinder head deterioration
Cylinder head gasket deteri-
oration

OVERHEATING CAUSE ANALYSIS
CO-7
< SERVICE INFORMATION >
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Except cool-
ing system
parts mal-
function— Overload on engineAbusive drivingHigh engine rpm under no
load
Driving in low gear for ex-
tended time
Driving at extremely high
speed
Powertrain system malfunc-
tion
— 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

THERMOSTAT AND WATER PIPING
CO-21
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3. Remove the engine room cover using power tool.
4. Disconnect the heater hose (heater core side).
5. Remove the 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 tempera-
ture 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-9, "Inspection".
• Start and warm up the engine. Visually check for leaks of the engine coolant.
SLC252B
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