engine coolant INFINITI QX56 2011 Factory Service Manual

ABBREVIATIONSGI-15
< HOW TO USE THIS MANUAL >
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ABBREVIATION DESCRIPTION E/T Exhaust temperature
EBD Electric brake force distribution EC Engine control
ECL Engine coolant level
ECM Engine control module ECT Engine coolant temperature
ECV Electrical control valve
EEPROM Electrically erasable programmable read only memory EFT Engine fuel temperature
EGR Exhaust gas recirculation
EGRT Exhaust gas recirculation temperature EGT Exhaust gas temperature
EOP Engine oil pressure EP Exhaust pressure
EPR Exhaust pressure regulator EPS Electronically controlled power steering
ESP Electronic stability program system
EVAP canister Evaporative emission canister EXC Exhaust control
ABBREVIATION DESCRIPTION FC Fan control
FCW Forward collision warning FIC Fuel injector controlFP Fuel pump
FR Front
FRP Fuel rail pressure FRT Fuel rail temperature
FTP Fuel tank pressure FTT Fuel tank temperature
ABBREVIATION DESCRIPTION GND GroundGPS Global positioning systemGST Generic scan tool
ABBREVIATION DESCRIPTION HBMC Hydraulic body-motion control systemHDD Hard disk drive
HO2S Heated oxygen sensor HOC Heated oxidation catalyst
Revision: 2010 May2011 QX56

HA-36
< REMOVAL AND INSTALLATION >
COOLER PIPE AND HOSE
9. Partly remove rear half of front fender protector RH. Refer to EXT-23, "FENDER PROTECTOR : Exploded
View".
10. Remove high-pressure pipe.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
LOW-PRESSURE PIPE
LOW-PRESSURE PIPE : Removal and InstallationINFOID:0000000006276176
CAUTION:
Perform lubricant return operation before each re frigeration system disassembly. However, if a large
amount of refrigerant or lubrican t is detected, never perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-22, "Per-
form Lubricant Return Operation".
2. Drain engine coolant from cooling system. Refer to CO-8, "
Draining".
3. Remove engine cover. Refer to EM-25, "
Removal and Installation".
4. Remove mouting bolt (A) and fixing pawls, and then remove relay box (1).
5. Remove mounting bolts (A), and then remove relay box bracket(1).
6. Remove front water outlet tube assembly mounting nut.
7. Remove mounting nuts, and then disconnec t mounting bracket from the vhiecle.
8. Remove mounting bolt, and then disconnect low-pressure pipe from low-pressure flexible hose. CAUTION:
Cap or wrap the joint of the A/C piping with suitab le material such as vinyl tape to avoid the entry
of air.
9. Remove mounting bolt, and then disconnect low-pressure pipe from expansion valve. CAUTION:
: Pawl
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Revision: 2010 May2011 QX56

A/C UNIT ASSEMBLYHA-43
< REMOVAL AND INSTALLATION >
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Perform lubricant return operati on before each refrigeration system disassembly. However, if a large
amount of refrigerant or lubricant is detected, n ever perform lubricant return operation. Refer to HA-
22, "Perform Lubricant Return Operation".
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-20, "Recy-
cle Refrigerant". (If equipped)
2. Drain engine coolant from cooling system. Refer to CO-8, "
Draining".
3. Remove clamps, and then disconnect front heater outlet hose from heater pipe.
CAUTION:
 Some coolant may spill when heater hoses are disconnected.
 Close off the coolant inlet and outlet on the heater core (2 locations) with shop cloths.
4. Remove mounting bolt, and then disconnect low-pressure pipe and high-pressure pipe from expansion valve.
CAUTION:
Cap or wrap the joint of the A/C piping and expan sion valve with suitable material such as vinyl
tape to avoid the entry of air.
5. Remove instrument panel assembly. Refer to IP-14, "
Removal and Installation".
6. Remove steering column mounting bolt and nuts. Refer to ST-34, "
Removal and Installation".
7. Move steering column assembly to a position where it does not inhibit work.
8. Disconnect harness clips, harness connectors, ground bol ts and blackets from steering member, and then
move the vehicle harness to the position without hindrance for work.
9. Remove mounting nuts, and then remove instrument stay (RH and LH).
10. Remove A/C unit assembly mounting bolts.
11. Remove mounting bolts, and then remove steering member from the vehicle.
12. Disconnect drain hose from A/C unit assembly, and then remove A/C unit assembly from the vehicle.
13. Remove mounting bolts, and then disconnect heater & cooling unit and blower unitassembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
NOTE:
Refer to CO-9, "
Refilling" when filling radiator with engine coolant.
EVAPORATOR
EVAPORATOR : Removal and InstallationINFOID:0000000006276184
REMOVAL
1. Remove heater & cooling unit assembly. Refer to HA-41, "Exploded View".
2. Remove heater core. Refer to HA-44, "
HEATER CORE : Removal and Installation".
3. Remove mounting screws, and then remove evaporator pipe cover.
4. Remove air mix door motor (RH). Refer to HAC-153, "
AIR MIX DOOR MOTOR : Removal and Installa-
tion".
5. Remove mounting screws, and then remove A/C cover.
6. Remove foot duct LH. Refer to VTL-11, "
FLOOR DUCT 1 : Removal and Installation".
7. Remove mounting screws, and then remove A/C lower case.
8. Remove intake sensor. Refer to HAC-150, "
Removal and Installation".
9. Remove evaporator assembly from heater & cooling unit assembly.
10. Remove mounting bolts, and then remove evaporator from evaporator assembly.
CAUTION:
Cap or wrap the joint of the evaporator and evaporat or pipe assembly with suitable material such as
vinyl tape to avoid the entry of air.
Revision: 2010 May2011 QX56

REAR A/C UNITHA-47
< REMOVAL AND INSTALLATION >
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REAR A/C UNIT ASSEMBLY
REAR A/C UNIT ASSEMBLY : Removal and InstallationINFOID:0000000006276188
REMOVAL
1. Use a refrigerant collecting equipment (for HF C-134a) to discharge the refrigerant. Refer to HA-22, "Per-
form Lubricant Return Operation".
2. Drain engine coolant from cooling system. Refer to HA-22, "
Perform Lubricant Return Operation".
3. Remove rear ventilator duct upper. Refer to VTL-12, "
REAR VENTILATOR DUCT UPPER : Removal and
Installation".
4. Remove rear ventilator duct lower. Refer to VTL-12, "
REAR VENTILATOR DUCT LOWER : Removal and
Installation".
5. Remove mounting bolt, and then disconnect rear cooler unit pipe assembly from rear cooler pipe assem-
bly.
1. Rear blower harness 2. Rear blower motor 3. Rear A/C unit case RH
4. Rear evaporator pipe assembly 5. O-ring 6. Rear expantion valve assembly
7. Rear A/C cooler pipe assembly 8. Pipe bracket 9. Grommet
10. Rear cooler pipe 11. Rear heater outlet tube assembly 12. Blind cap
13. Rear heater inlet tube assembly 14. Clamp 15. Clamp
16. Shild plate 17. Bracket 18. Rear A/C unit case LH
19. Rear evapolator 20. Drain hose 21. Rear air mix door
22. Rear heater core 23. Rear heater pipe clamp 24. Rear A/C unit upper case (front)
25. Rear mode door 26. Rear A/C unit upper case (rear) 27. Air mix door harness
28. Rear intake sensor 29. Packing
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0641GB
Revision: 2010 May2011 QX56

REAR A/C UNITHA-49
< REMOVAL AND INSTALLATION >
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5. Pull out heater core (1) from rear A/C unit assembly.
INSTALLATION
Note the following item, and install in the reverse order of removal.
NOTE:
Refer to CO-9, "
Refilling" when filling radiator with engine coolant.
EXPANSION VALVE
EXPANSION VALVE : Removal and InstallationINFOID:0000000006276192
REMOVAL
1. Remove rear A/C unit assembly. Refer to HA-47, "REAR A/C UNIT ASSEMBLY : Removal and Installa-
tion".
2. Disassembly rear A/C unit assembly.
3. Remove mounting bolts, and then disconnect rear exp ansion valve assembly from rear evaporator pipe
assembly and rear cooler pipe assembly.
INSTALLATION
Note the following items, and install in the reverse order of removal.
CAUTION:
 Replace O-rings with new ones. Then apply compressor oil to them when installing.
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
JMIIA0685ZZ
Revision: 2010 May2011 QX56

HAC-6
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
COMPONENT PARTS
SYSTEM DESCRIPTION
COMPONENT PARTS
FRONT AUTOMATIC AIR CONDITIONING SYSTEM
FRONT AUTOMATIC AIR CONDITIONING
SYSTEM : Component Parts Location
INFOID:0000000006275848
1. Preset switch 2. Engine coolant temperature sensor
Refer to EC-16, "
Component Parts
Location". 3. IPDM E/R
Refer to PCS-4, "
Component Parts
Location".
4. ECM Refer to EC-16, "
Component Parts
Location"
5. Refrigerant pressure sensor 6. Ambient sensor
7. Magnet clutch 8. AV control unit Refer to AV- 9 , "
Component Parts Lo-
cation". 9. Combination meter
Refer to MWI-6, "
METER SYSTEM :
Component Parts Location".
10. Sunload sensor 11. Front display 12. Upper ventilator door motor
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Revision: 2010 May2011 QX56

COMPONENT PARTSHAC-7
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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FRONT AUTOMATIC AIR CONDITIONING SYSTEM : Component Description
INFOID:0000000006275849
13. Aspirator 14. Front air mix door motor (Driver side) 15. Intake sensor
16. Front mode door motor 17. Front air mix door motor (Passenger
side)18. Intake door motor
19. Front blower motor 20. A/C auto amp. 21. Front in-vehicle sensor
A. Left side of heater & cooling unit as- sembly B. Right side of heater & cooling unit as-
sembly C. Back side of blower unit assembly
D. Cluster lid C is removed E. Ins trument lower panel LH is re-
moved
Component Description
Ambient sensor Ambient sensor measures ambient air temperature. The sensor uses a
thermistor which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature increases.
AV c o n t r o l u n i t AV control unit transmits front A/C control operation signal to A/C auto amp.
via CAN communication line.
A/C auto amp. A/C auto amp. controls front automatic air conditioning system by inputting
and calculating signals from each sensor and each switch. A/C auto amp.
has self-diagnosis function. Diagnosis of front automatic air conditioning
system can be performed quickly.
Blower unit Front blower motor Refer to
HAC-12
.
Intake door motor The LCU (Local Control Unit) is installed to intake door motor so as to per-
form the multiplex commu
nication control (LIN).
Refer to HAC-18, "
FRONT AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
Combination meter Combination meter transmits vehicle speed signal to A/C auto amp. via
CAN communication line.
ECM ECM controls compressor according to status of engine and refrigerant.
ECM transmits engine coolant temperature signal to A/C auto amp. via
CAN communication line.
Engine coolant temperature sensor Engine coolant temperature sensor measures engine coolant temperature.
The sensor uses a thermistor which is sensitive to the change in tempera-
ture. The electrical resistance of the thermistor decreases as temperature
increases.
Front display Front display indicates operation status of front automatic air conditioning
system.
Front in-vehicle sensor Front in-vehicle sensor measures temperature of intake air that flows
through aspirator to passenger room. The sensor uses a thermistor which
is sensitive to the change in temperature. The electrical resistance of the
thermistor decreases as temperature increases.
Revision: 2010 May2011 QX56

COMPONENT PARTSHAC-9
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONING]
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REAR AUTOMATIC AIR CONDITIONING SY STEM : Component Parts Location
INFOID:0000000006275850
1. Rear A/C control 2. Preset switch 3. Engine coolant temperature sensor
Refer to EC-16, "
Component Parts
Location".
4. ECM Refer to EC-16, "
Component Parts
Location". 5. Ambient sensor 6. AV control unit
Refer to AV- 9 , "
Component Parts Lo-
cation".
7. Combination meter Refer to MWI-6, "
METER SYSTEM :
Component Parts Location". 8. Sunload sensor 9. Front display
10. Rear mode door motor 11. Rear air mix door motor 12. Rear in-vehicle sensor
13. Rear blower motor 14. Rear A/C solenoid valve 15. Rear A/C relay
16. Intake sensor 17. A/C auto amp.
A. Right side of rear A/C unit assembly B. Left side of rear A/C unit assembly C. Back side of engine room (RH)
D. Left side of heater & cooling unit as- sembly E. Cluster lid C is removed
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Revision: 2010 May2011 QX56

HAC-10
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
COMPONENT PARTS
REAR AUTOMATIC AIR CONDITIONING SYSTEM : Component Description
INFOID:0000000006275851
ACCS (ADVANCED CLIMATE CONTROL SYSTEM)
Component Description
Ambient sensor Ambient sensor measures ambient air temperature. The sensor uses a
thermistor which is sensitive to the change in temperature. The electrical
resistance of the thermistor decreases as temperature increases.
AV c o n t r o l u n i t AV control unit transmits front A/C control operation signal to A/C auto amp.
via CAN communication line.
A/C auto amp. A/C auto amp. controls rear automatic air conditioning system by inputting
and calculating signals from each sensor and each switch. A/C auto amp.
has self-diagnosis function. Diagnosis of rear automatic air conditioning
system can be performed quickly.
Combination meter Combination meter transmits vehicle speed signal to A/C auto amp. via
CAN communication line.
ECM ECM transmits engine coolant temperature signal to A/C auto amp. via
CAN communication line.
Engine coolant temperature sensor Engine coolant temperature sensor measures engine coolant temperature.
The sensor uses a thermistor which is sensitive to the change in tempera-
ture. The electrical resistance of the thermistor decreases as temperature
increases.
Front display Front display indicates operation status of rear automatic air conditioning
system.
Heater & cooling unit
assembly Intake sensor Intake sensor measures temperature of front evaporator fin temperature.
The sensor uses a thermistor which is sensitive to the change in tempera-
ture. The electrical resistance of the thermistor decreases as temperature
increases.
Preset switch Preset switch is integrated with front A/C control and AV operation switch.
Front A/C control operation signal is transmitted from preset switch to AV
control unit via communication line.
Rear A/C control The operation of the rear A/C control is communicated with the A/C auto
amp. via communication line.
Rear A/C relay Power is supplied to the rear A/C solenoid valve through rear A/C relay with
A/C auto amp. control.
Rear A/C unit assem-
bly Rear air mix door motor
The LCU (Local Contro
l Unit) is installed to rear air mix door motor so as to
perform the multiplex communication control (LIN).
Refer to HAC-26, "
REAR AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
Rear A/C solenoid valve Rear A/C solenoid valve operates by power supply from rear A/C relay and
opens refrigerant line to rear evaporator.
Rear blower motor Refer to HAC-13
.
Rear in-vehicle sensor Rear in-vehicle sensor measures temperature of intake air that flows
through rear blower motor to passenger room. The sensor uses a ther-
mistor which is sensitive to the change in temperature. The electrical resis-
tance of the thermistor decreases as temperature increases.
Rear mode door motor The LCU (Local Control Unit) is installed to rear mode door motor so as to
perform the multiplex communication control (LIN).
Refer to
HAC-26, "
REAR AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
Sunload sensor Sunload sensor measures sunload amount. This sensor is a dual system
so that sunload for driver side and passenger side are measured separate-
ly. This sensor converts sunload amount to voltage signal by photodiode
and transmits to A/C auto amp..
Revision: 2010 May2011 QX56

HAC-16
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
SYSTEM
 When air outlet is VENT or B/L, the minimum air flow is changed
depending on sunload.
STARTING AIR FLOW CONTROL
 When front blower motor is activated, A/C auto amp. graduallyincreases duty ratio of front blower motor control signal to prevent
a sudden increase in discharge air flow.
 It takes approximately 8 seconds for air flow to reach HI from LOW.
LOW COOLANT TEMPERATURE STARTING CONTROL
If the engine coolant temperature is 56 °C (133 °F) or less, to prevent
a cold discharged air flow, A/C auto amp. suspends front blower
motor activation for the maximum 150 seconds depending on target
front air mix door opening angle. After this, front blower motor control
signal is increased gradually, and front blower motor is activated.
HIGH IN-VEHICLE TEMPERATURE STARTING CONTROL
When front evaporator fin temperature is high [intake sensor value is 35°C (95 °F) or more], to prevent a hot
discharged air flow, A/C auto amp. suspends front blower motor activation for approximately 3 seconds so that
front evaporator is cooled by refrigerant.
FAN SPEED CONTROL AT DOOR MOTOR OPERATION
When front mode door motor is activated while air flow is more than the specified value, A/C auto amp.
reduces temporarily fan speed wo that front mode door moves smoothly.
FRONT AUTOMATIC AIR CONDITIONIN G SYSTEM : Air Inlet ControlINFOID:0000000006275863
The intake door is automatically controlled by the temperature set-
ting, ambient temperature, in-vehicle temperature (front side), intake
temperature, amount of sunload and ON/OFF operation of the com-
pressor.
Intake door automatic control selects FRE, 20% FRE, or REC
depending on a target front air mix door opening angle, based on in-
vehicle temperature (front side) , ambient temperature, and sunload.
JMIIA0735GB
JMIIA0736GB
JMIIA0737GB
JMIIA0732GB
Revision: 2010 May2011 QX56