2011 INFINITI QX56 Cooling

HA-42
< REMOVAL AND INSTALLATION >
A/C UNIT ASSEMBLY
HEATER & COOLING UNIT ASSEMBLY
HEATER & COOLING UNIT ASSEMBLY : Removal and InstallationINFOID:0000000006276183
CAUTION:
1. Rear heater packing 2. A/C case RH 3. Foot duct RH
4. Heater core assembly 5. Heater pipe cover 6. Evaporator pipe cover
7. Evaporator pipe assembly 8. O-ring 9. Expansion valve
10. Grommet 11. Heater packing 12. Drain hose assembly
13. A/C case lower 14. A/C cover 15. Evaporator
16. Intake sensor 17. Dfroster door 18. Upper ventirator door
19. Slide door unit 20. A/C case center 21. A/C case LH
22. Foot duct LH 23. Aspirator 24. Aspirator hose
25. In-vehicle sensor 26. Foot door LH 27. Foot door RH
28. Ventirator door 29. Ventirator packing
Refer to GI-4, "
Components" for symbols in the figure.
JMIIA0629GB
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

HA-44
< REMOVAL AND INSTALLATION >
A/C UNIT 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.
 When install the intake sensor, set the same position before replacement.
 Never rotate the bracket insertion part when removing and installing the intake sensor.
 Perform lubricant adjusting procedure af ter installing new evaporator. Refer to HA-22, "
Lubricant
Adjusting Procedure for Components Replacement Except Compressor".
HEATER CORE
HEATER CORE : Removal and InstallationINFOID:0000000006276185
REMOVAL
1. Remove heater & cooling unit assembly. Refer to HA-42, "HEATER & COOLING UNIT ASSEMBLY :
Removal and Installation".
2. Remove mounting screws, and then remove heater core pipe cover.
3. Remove mode door motor. Refer to HAC-153, "
MODE DOOR MOTOR : Removal and Installation".
4. Remove main link, foot door link and foot door lever. Refer to HAC-152, "
Exploded View".
5. Remove mounting screws, and then remove foot duct (assist side). Refer to VTL-11, "
FLOOR DUCT 1 :
Removal and Installation".
6. Pull out heater core (1) from heater & cooling unit 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 ti them when installing
 Check for leakages when recharging refrigerant. Refer to HA-18, "
Leak Test".
EXPANSION VALVE
EXPANSION VALVE : Removal and InstallationINFOID:0000000006276186
CAUTION:
Perform lubricant return operation before each refrigeration 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-20, "Recy-
cle Refrigerant".
2. Remove A/C unit assembly. Refer to HA-42, "
HEATER & COOLING UNIT ASSEMBLY : Removal and
Installation".
3. Remove mounting bolts, and then remove expansion valve. CAUTION:
Cap or wrap the joint of the evaporator pipe assembly and expansion valve with suitable material
such as vinyl tape to avoid the entry of air.
INSTALLATION
Note the following items, and install in the reverse order of removal.
JMIIA0684ZZ
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

HAC-4
FRONT AUTOMATIC AIR CONDITIONING
SYSTEM .......................................................... .
133
Diagnosis Chart By Symptom .............................. ..133
REAR AUTOMATIC AIR CONDITIONING
SYSTEM .......................................................... .
135
Diagnosis Chart By Symptom .............................. ..135
ACCS (ADVANCE CLIMATE CONTROL
SYSTEM) .........................................................
137
Symptom Table ................................................... ..137
INSUFFICIENT COOLING ...............................138
FRONT AIR CONDITIONER .................................. ..138
FRONT AIR CONDITIONER : Description ............138
FRONT AIR CONDITIONER : Diagnosis Proce-
dure .......................................................................
138
REAR AIR CONDITIONER .................................... ..139
REAR AIR CONDITIONER : Description ...............139
REAR AIR CONDITIONER : Diagnosis Procedure
..
139
INSUFFICIENT HEATING .............................. .140
FRONT AIR CONDITIONER .................................. ..140
FRONT AIR CONDITIONER : Description ............140
FRONT AIR CONDITIONER : Diagnosis Proce-
dure .......................................................................
140
REAR AIR CONDITIONER .................................... ..140
REAR AIR CONDITIONER : Description ...............141
REAR AIR CONDITIONER : Diagnosis Procedure
..
141
COMPRESSOR DOSE DOT OPERATE ........ .142
Description ........................................................... ..142
Diagnosis Procedure .............................................142
REMOVAL AND INSTALLATION ..............144
FRONT A/C CONTROL .................................. .144
Removal and Installation ..................................... ..144
REAR A/C CONTROL .....................................145
Removal and Installation ..................................... ..145
A/C AUTO AMP. ..............................................146
Removal and Installation ..................................... ..146
AMBIENT SENSOR ..........................................147
Removal and Installation ...................................... .147
IN-VEHICLE SENSOR ......................................148
FRONT A/C UNIT ASSEMBLY ...............................148
FRONT A/C UNIT ASSEMBLY : Removal and In-
stallation ............................................................... .
148
REAR A/C UNIT ASSEMBLY .................................148
REAR A/C UNIT ASSEMBLY : Removal and In-
stallation ............................................................... .
148
SUNLOAD SENSOR ........................................149
Removal and Installation ...................................... .149
INTAKE SENSOR .............................................150
Exploded View ..................................................... .150
Removal and Installation .......................................150
EXHAUST GAS/OUTSIDE ODOR SENSOR ...151
Removal and Installation ...................................... .151
DOOR MOTOR .................................................152
Exploded View ..................................................... .152
MODE DOOR MOTOR ........................................... .153
MODE DOOR MOTOR : Removal and Installation .153
AIR MIX DOOR MOTOR ........................................ .153
AIR MIX DOOR MOTOR : Removal and Installa-
tion ....................................................................... .
153
INTAKE DOOR MOTOR ........................................ .153
INTAKE DOOR MOTOR : Removal and Installa-
tion ........................................................................
153
UPPER VENTILATOR DOOR MOTOR ..................154
UPPER VENTILATOR DOOR MOTOR : Removal
and Installation ..................................................... .
154
REAR MODE DOOR MOTOR ................................ .154
REAR MODE DOOR MOTOR : Removal and In-
stallation ................................................................
154
REAR AIR MIX DOOR MOTOR ............................. .154
REAR AIR MIX DOOR MOTOR : Removal and In-
stallation ................................................................
154
IONIZER ............................................................155
Exploded View ..................................................... .155
Removal and Installation .......................................155
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

HAC-8
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONING]
COMPONENT PARTS
REAR AUTOMATIC AIR CONDITIONING SYSTEM
Heater & cooling unit
assemblyAspirator Refer to
HAC-12
.
Front air mix door motor (Driver
side) The LCU (Local Control Unit) is installe
d to front air mix door motor (driver
side) so as to perform the multiplex communication control (LIN).
Refer to HAC-18, "
FRONT AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
Front air mix door motor (Pas-
senger side) The LCU (Local Control Unit) is installed to front air mix door motor (pas-
senger side) so as to perform the multiplex communication control (LIN).
Refer to
HAC-18, "
FRONT AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
Front mode door motor The LCU (Local Control Unit) is installed to front mode door motor so as to
perform the multiplex communication control (LIN).
Refer to
HAC-18, "
FRONT AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
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.
Upper ventilator door motor The LCU (Local Control Unit) is installed to upper ventilator door motor so
as to perform the multiplex communication control (LIN).
Refer to
HAC-18, "
FRONT AUTOMATIC AIR CONDITIONING SYSTEM :
Door Control".
IPDM E/R A/C relay is integrated in
IPDM E/R. IPDM E/R op erates A/C relay when A/
C compressor request signal is received from ECM via CAN communica-
tion line.
Magnet clutch The magnet clutch is the device that drives the compressor with the signal
from IPDM E/R. Compressor is driven by the magnet clutch which is mag-
netized by electric power supply. IPDM controls magnet clutch by turning
the built in A/C relay to ON
⇔ OFF according to ECM request.
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.
Refrigerant pressure sensor Refer to HAC-13
.
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..
Component Description
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
JMIIA0813ZZ
Revision: 2010 May2011 QX56