2009 INFINITI QX56 engine

HIGH-PRESSURE PIPEHA-41
< ON-VEHICLE REPAIR >
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HIGH-PRESSURE PIPE
Removal and Installation for High-Pressure PipeINFOID:0000000003775316
REMOVAL
1. Remove the cowl top extension. Refer to EXT-18, "Removal and Installation".
2. Disconnect the battery negative termi nal and positive battery terminal.
3. Reposition the IPDM E/R aside.
4. Remove the front left wheel and tire assembly. Refer to MA-29, "Rotation"
.
5. Position aside the front floor insulator.
6. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure"
.
7. Remove the low pressure pipe. Refer to HA-37, "Removal and Installation for Low-Pressure Pipe"
.
8. Remove the high-pressure pipe. CAUTION:
Cap or wrap the joint of the pipe with suitable mate rial such as vinyl tape to avoid the entry of air.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-ring of the high-pressure pipe with a new one, then apply compressor oil to it when
installing it.
 After charging refrigerant, check for leaks.
Removal and Installation for Rear High- and Low-Pressure A/C and Heater Core Pipes
INFOID:0000000003775317
REMOVAL
1. Discharge the refrigerant from the A/C system. Refer to HA-20, "HFC-134a (R-134a) Service Procedure".
2. Drain the coolant from the engine cooling system. Refer to CO-11, "Changing Engine Coolant"
.
3. Disconnect the underfloor rear heater hoses (1 and 2) from the rear heater pipes underneath the vehicle.
 : Front
4. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the under-
floor rear high- and low-pressu re pipes underneath the vehicle.
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
5. Remove the rear high- and low-pressure pipes nuts (B).
NOTE:
The remaining steps are performed inside the rear luggage area of the vehicle.
6. Remove the luggage side finisher lower RH. Refer to INT-19, "Removal and Installation"
.
7. Disconnect the rear heater core hoses (1 and 2) from the rear heater core (3).
 : Front
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Revision: December 20092009 QX56

HA-42
< ON-VEHICLE REPAIR >
HIGH-PRESSURE PIPE
8. Remove the rear high- and low-pressure pipes bracket bolt (A)to release the bracket.
 Rear blower motor (1)
 : Front
9. Remove the rear high- and low-pressure pipes bolt (A) to dis- connect the rear high- and low-pressure pipes from the rear
expansion valve (1).
 : Front
CAUTION:
Cap or wrap the joint of the pipes with suitable material
such as vinyl tape to avoid the entry of air.
10. Disconnect the following electrical connectors:  Rear air mix door motor (1)
 Rear variable blower control (2)
 Rear blower motor (3)
 : Front
11. Disconnect the ducts from the rear heater and cooling unit assembly. Refer to HA-29, "Component"
.
12. Remove the rear heater and cooling unit assembly. CAUTION:
Cap or wrap the joint of the pipes with suitable material such as viny l tape to avoid the entry of air.
13. Remove the rear high- and low-pressure A/C pipes.
INSTALLATION
Installation is in the reverse order of removal.
Refer to HA-29, "Component"
.
CAUTION:
 Replace the O-rings on the rear high- and low-pr essure A/C pipes with a new ones, then apply com-
pressor oil to them for installation.
 After charging the refrigerant, check for leaks.
Removal and Installation for Underfloor Rear High- and Lo w-Pressure A/C and Heater
Core Pipes
INFOID:0000000003775318
REMOVAL
1. Drain the engine coolant. Refer to CO-11, "Changing Engine Coolant".
2. Disconnect the battery negative terminal.
3. Disconnect the generator harness.
4. Discharge the refrigerant. Refer to HA-20, "HFC-134a (R-134a) Service Procedure"
.
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HAC-4
< BASIC INSPECTION >[AUTOMATIC AIR CONDITIONER]
INSPECTION AND ADJUSTMENT
INSPECTION AND ADJUSTMENT
Operational Check (Front)INFOID:0000000003775325
The purpose of the operational check is to
confirm that the system operates properly.
CHECKING MEMORY FUNCTION
1. Set the temperature to 32 ° (90 °F).
2. Press the OFF switch.
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous temperature.
7. Press the OFF switch.
If NG, go to trouble diagnosis procedure for HAC-122, "
Memory Function Check".
If OK, continue with next check.
CHECKING BLOWER
1. Press the blower speed control switch (+) once, blower should operate on low speed. The fan display should have one bar lit (on display).
2. Press the blower speed control switch (+) again, and continue checking blower speed and fan display until
all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for HAC-52, "
Front Blower Motor Diagnosis Procedure".
If OK, continue with next check.
CHECKING DISCHARGE AIR
1. Press MODE switch four times and the DEF switch.
2. Each position indicator should change shape (on display).
3. Confirm that discharge air comes out according to the air distribution table. Refer to HAC-16, "
Discharge
Air Flow (Front)".
Mode door position is checked in the next step.
If NG, go to trouble diagnosis procedure for HAC-27, "
Mode Door Motor (Front) Diagnosis Procedure".
If OK, continue the check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual inspection) and intake door position is at
fresh when the DEF or D/F is selected.
CHECKING RECIRCULATION ( , ONLY)
1. Press recirculation ( ) switch one time. Recirculation indicator should illuminate.
2. Press recirculation ( ) switch one more time. Recirculation indicator should go off.
3. Listen for intake door position change (blower sound should change slightly).
If NG, go to trouble diagnosis procedure for HAC-43, "
Intake Door Motor Diagnosis Procedure".
If OK, continue the check.
NOTE:
Confirm that the compressor clutch is engaged (sound or vis ual inspection) and intake door position is at fresh
when the DEF or D/F is selected. REC ( ) is not allowed in DEF ( ) D/F ( ) or FOOT ( ).
CHECKING TEMPERATURE DECREASE
1. Rotate temperature control dial (drive or passenger) counterclockwise until 18° C (60°F) is displayed.
2. Check for cold air at appropriate discharge air outlets. Conditions : Engine running and at normal operating temperature
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INSPECTION AND ADJUSTMENTHAC-5
< BASIC INSPECTION > [AUTOMATIC AIR CONDITIONER]
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If NG, listen for sound of air mix door motor operat ion. If OK, go to trouble diagnosis procedure for HAC-110,
"Component Function Check". If air mix door motor appears to be malfunctioning, go to HAC-32, "Air Mix Door
Motor Component Function Check".
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Rotate temperature control dial clockwise (drive 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 operat ion. If OK, go to trouble diagnosis procedure for HAC-118,
"Component Function Check". If air mix door motor appears to be malfunctioning, go to HAC-32, "Air Mix Door
Motor Component Function Check".
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, compre ssor clutch will already be engaged and cannot be turned off.
If NG, go to trouble diagnosis procedure for HAC-73, "
Magnet Clutch Diagnosis Procedure".
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 HAC-90, "
A/C Auto Amp Power and Ground Diagnosis Proce-
dure", then if necessary, trouble diagnosis procedure for HAC-73, "Magnet Clutch Diagnosis Procedure".
If all operational checks are OK (symptom cannot be duplicated), go to malfunction Simulation Tests in HAC-
3, "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 HAC-109, "
SymptomMatrixChart", and
perform applicable troubl e diagnosis procedures.
Operational Check (Rear)INFOID:0000000003775326
The purpose of the operational check is to confirm that the system operates properly.
CHECKING REAR BLOWER MOTOR
1. Turn the ignition switch ON.
2. Rotate rear air control (front) blower control dial to low speed.
3. Rotate the blower control dial clockwise and continue checking blower speed until all speeds are checked.
4. Leave blower on maximum speed.
5. Press the REAR CTRL switch from the rear air control (front).
6. Rotate rear air control (rear) blower control dial to low speed.
7. Rotate the blower control dial clockwise and continue checking blower speed until all speeds are checked.
8. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for HAC-57, "
Rear Blower Motor Component Function Check".
If OK, continue with next check.
CHECKING REAR DISCHARGE AIR
Conditions : Engine running and at normal operating temperature
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FUNCTION INFORMATIONHAC-7
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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FUNCTION DIAGNOSIS
FUNCTION INFORMATION
Component Part LocationINFOID:0000000003775327
ENGINE COMPARTMENT
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1. Water valve F68 2. Refrigerant pressure sensor E48 3. Ambient sensor E1
4. A/C compressor F3
Revision: December 20092009 QX56

HAC-50
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
BLOWER MOTOR CONTROL SYSTEM
BLOWER MOTOR CONTROL SYSTEM
System DescriptionINFOID:0000000003775356
SYSTEM DESCRIPTION
Component Parts
Blower speed control
system components are:• A/C auto amp.
• A/C and AV switch assembly
• Variable blower control
• Front blower motor relay
• Front blower motor
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
Automatic Mode
In the automatic mode, the blower motor speed is calc ulated by the A/C auto amp. and variable blower control
based on input from the in-vehicle sensor, optical sens or, intake sensor and ambient sensor, and potentio tem-
perature control (PTC).
When the air flow is increased, the blower motor s peed is adjusted gradually to prevent a sudden increase in
air flow.
In addition to manual air flow control and the usual automat ic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.
Starting Blower Speed Control
Start up from cold soak condition (Automatic mode).
In a cold start up condition where the engine coolant temperature is below 50 °C (122° F), the blower will not
operate at blower speed 1 for a short period of time (up to 210 seconds). The exact start delay time varies
depending on the ambient and engine coolant temperatures.
In the most extreme case (very low ambient temper ature) the blower starting delay will be 210 seconds as
described above. After the coolant temperature reaches 50 °C (122° F), or the 210 seconds has elapsed, the
blower speed will increase to the objective blower speed.
Start up from usual operating or hot soak condition (Automatic mode).
The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually
rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).
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HAC-52
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
BLOWER MOTOR CONTROL SYSTEM
YES >> Refer to HAC-24, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 5.
5.PERFORM A/C AND AV SWITCH ASSEMBLY SELF-DIAGNOSIS
Perform self-diagnosis to check the A/C and AV switch assembly. Refer to HAC-23, "
A/C and AV Switch
Assembly Self-Diagnosis".
Is the inspection results normal?
YES >> GO TO 6.
NO >> Replace A/C and AV switch assembly. Refer to VTL-7, "
Removal and Installation".
6.CHECK BLOWER MOTOR OPERATION
Check and verify blower motor operates manually in all speeds.
Does blower motor operate in all speeds?
YES >> GO TO 7.
NO >> Refer to HAC-52, "
Front Blower Motor Diagnosis Procedure".
7.CHECK ENGINE COOLANT TE MPERATURE SENSOR CIRCUIT
Check engine coolant temperature sensor circuit. Refer to EC-121, "
Diagnosis Procedure".
Is the inspection results normal?
YES >> GO TO 8.
NO >> Replace enging coolant temperature sensor.
8.RECHECK FOR ANY SYMPTOMS
Perform a complete operational check for any symptoms. Refer to HAC-4, "
Operational Check (Front)".
Does another symptom exist?
YES >> Refer to HAC-3, "How to Perform Trouble Diagnosis For Quick And Accurate Repair" .
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
Front Blower Motor Diagnosis ProcedureINFOID:0000000003775358
SYMPTOM: Blower motor operation is malfunctioning.
DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR
SYMPTOM: Blower motor operation is malfunctioning under starting
blower speed control.
1.CHECK FUSES
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REAR AIR CONTROL SYSTEMHAC-63
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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1. Start and run engine to operating temperature.
2. Turn the rear blower motor to maximum speed from the rear air control (front).
3. Turn rear air control (front) temperature contro l dial clockwise and then counterclockwise (REAR CTRL
indicator off).
4. Check for hot air at rear discharge air outlets in the maximum heat position and cold air at discharge air outlets in the maximum cold position.
Does the rear air control (front) operate properly?
YES >> GO TO 3.
NO >> Check rear air control (front). Refer to HAC-63, "
Air Mix Door Motor (Rear) Diagnosis Procedure".
3.CONFIRM SYMPTOM BY PERFORMING REAR AIR CONTROL (REAR) AIR MIX DOOR MOTOR OPER-
ATIONAL CHECK
1. Press the REAR CTRL switch on rear air control (front) to send control to t he rear air control (rear).
2. Turn rear air control (rear) temperature control dial slowly clockwise and then counterclockwise (REAR
CTRL indicator on).
3. Check for hot air at rear discharge air outlets in the maximum heat position and cold air at rear discharge
air outlets in the maximum cold position.
Does the rear air control (rear) operate properly?
YES >> GO TO 4.
NO >> Check rear air control (rear). Refer to HAC-59, "
Rear Air Control (Rear) Diagnosis Procedure #2".
4.CONFIRM SYMPTOM BY PERFORMING REAR AIR CONTROL (FRONT) MODE OPERATIONAL CHECK
1. Press the REAR CTRL switch on rear air control (front) (REAR CTRL indicator off).
2. Press each mode switch and check for proper air discharge at the appropriate locations.
Does the rear air control (front) operate properly?
YES >> GO TO 5.
NO >> Check mode door motor (rear). Refer to HAC-67, "
Mode Door Motor (Rear) Diagnosis Proce-
dure".
5.CONFIRM SYMPTOM BY PERFORMING REAR AIR CONTROL (REAR) MODE OPERATIONAL CHECK
1. Press the REAR CTRL switch on rear air control (front) to send control to t he rear air control (rear).
2. Press each mode switch and check for proper air discharge at the appropriate locations.
Does the rear air control (rear) operate properly?
YES >> System OK.
NO >> Replace rear air control (rear). Refer to VTL-7, "
Removal and Installation".
Air Mix Door Motor (Rear) Diagnosis ProcedureINFOID:0000000003775367
DIAGNOSTIC PROCEDURE FOR INOPERATIVE AIR MIX DOOR MOTOR (REAR)
SYMPTOM:
• Temperature control (rear) operation is malfunctioning.
1.CHECK REAR AIR CONTROL (FRONT) POWER SUPPLY
1. Disconnect rear air control (front) harness connector.
2. Turn ignition switch ON.
3. Check voltage between rear air control (front) harness connec- tor R108 terminal 1 and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair harness or connector.
2.CHECK REAR AIR CONTROL (FRONT) LIN BUS VOLTAGE Battery voltage should exist.
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Revision: December 20092009 QX56