2009 INFINITI QX56 200

IN-VEHICLE SENSORHAC-83
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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1. Disconnect in-vehicle sensor connector.
2. Turn ignition switch ON.
3. Check voltage between in-vehicle sensor harness connector M32 terminal 4 and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 5.
3.CHECK CIRCUIT CONTINUITY BETWEEN IN-V EHICLE SENSOR AND A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector M49.
3. Check continuity between in-vehicle sensor harness connector M32 (B) terminal 1 and A/C auto amp. harness connector M49
(A) terminal 26.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair harness or connector.
4.CHECK IN-VEHICLE SENSOR
Check in-vehicle sensor. Refer to HAC-84, "
In-Vehicle Sensor Component Inspection".
Is the inspection result normal?
YES >> 1. Replace A/C auto amp. Refer to VTL-7, "Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
NO >> 1. Replace in-vehicle sensor. Refer to VTL-9, "
Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
5.CHECK CIRCUIT CONTINUITY BETWEEN IN-V EHICLE SENSOR AND A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between in-vehicle sensor harness connector M32 (B) terminal 4 and A/C auto amp. harness connector M50
(A) terminal 32.
4. Check continuity between in-vehicle sensor harness connector M32 (B) terminal 4 and ground.
Is the inspection result normal?
YES >> 1. Replace A/C auto amp. Refer to VTL-7, "Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
NO >> Repair harness or connector.
6.CHECK CIRCUIT CONTINUITY BETW EEN IN-VEHICLE SENSOR MOTOR AND A/C AUTO AMP. (SELF-
DIAGNOSIS CODES 30, 31, 44, 46 OR DTC B2578, B2579)
4 - Ground
: Approx. 5V.
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1 - 26 : Continuity should exist.
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4 - 32: Continuity should exist.
4 - Ground Continuity should not exist.
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Revision: December 20092009 QX56

HAC-84
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
IN-VEHICLE SENSOR
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector and in-vehicle sensor con-
nector.
3. Check continuity between in-vehicle sensor harness connector M32 (B) terminal 3 and A/C auto amp. harness connector M50
(A) terminal 31.
4. Check continuity between in-vehicle sensor harness connector M32 (B) terminal 3 and ground.
Is the inspection result normal?
YES >> 1. Replace A/C auto amp. Refer to VTL-7, "Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
NO >> Repair harness or connector.
In-Vehicle Sensor Component InspectionINFOID:0000000003775379
COMPONENT INSPECTION
In-vehicle Sensor
After disconnecting in-vehicle sensor connector M32, measure resis-
tance between terminals 1 and 4 at sensor component side, using
the table below.
If NG, replace in-vehicle sensor. Refer to VTL-9, "
Removal and
Installation".
3 - 31
: Continuity should exist.
2 - Ground : Continuity should exist.
3 - Ground : Continuity should not exist.
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Temperature °C ( °F) Resistance kΩ
− 15 (5) 21.40
− 10 (14) 16.15
− 5 (23) 12.29
0 (32) 9.41
5 (41) 7.27
10 (50) 5.66
15 (59) 4.45
20 (68) 3.51
25 (77) 2.79
30 (86) 2.24
35 (95) 1.80
40 (104) 1.45
45 (113) 1.18
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Revision: December 20092009 QX56

OPTICAL SENSORHAC-85
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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OPTICAL SENSOR
Component DescriptionINFOID:0000000003775380
COMPONENT DESCRIPTION
The optical sensor (1) is located in the center of the defroster grille. It
detects sunload entering through windshield by means of a photo
diode. The sensor converts the sunload into a current value which is
then input into the A/C auto amp.
OPTICAL INPUT PROCESS
The A/C auto amp. includes a processing circuit which averages the variations in detected sunload over a
period of time. This prevents adjustments in the ATC system operation due to small or quick variations in
detected sunload.
For example, consider driving along a road bordered by an occasional group of large trees. The sunload
detected by the optical sensor will vary whenever the tr ees obstruct the sunlight. The processing circuit aver-
ages the detected sunload over a period of time, so that the (insignificant) effect of the trees momentarily
obstructing the sunlight does not cause any change in t he ATC system operation. On the other hand, shortly
after entering a long tunnel, the system will recognize the change in sunload, and the system will react accord-
ingly.
Optical Sensor Diagnosis ProcedureINFOID:0000000003775381
DIAGNOSTIC PROCEDURE FOR OPTICAL SENSOR
SYMPTOM: Optical sensor circuit is open or shorted. Using the
CONSULT-III, DTC B257F or B2580 is displayed. Without a CON-
SULT-III, code 50 or 52 is indicated on A/C auto amp. as a result of
conducting self-diagnosis.
1.CHECK CIRCUIT CONTINUITY BETWEEN OP TICAL SENSOR AND A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector and optical sensor connec- tor.
3. Check continuity between optical sensor harness connector M302 (B) terminals 1 and 2 and A/C auto amp. harness connec-
tor M50 (C) terminal 42 and M49 (A) terminal 1.
4. Check continuity between optical sensor harness connector M302 (B) terminal 1 and 2 and ground.
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1 - 1 : Continuity should exist.
2 - 42 : Continuity should exist.
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Revision: December 20092009 QX56

HAC-86
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
OPTICAL SENSOR
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair harness or connector.
2.CHECK CIRCUIT CONTINUITY BETW
EEN OPTICAL SENSOR AND BCM
1. Disconnect BCM connector.
2. Check continuity between optical sensor harness connector M302 (B) terminal 3 and BCM har ness connector M18 (A) termi-
nal 18.
3. Check continuity between optical sensor harness connector M302 (B) terminal 3 and ground.
Is the inspection result normal?
YES >> Replace optical sensor. Refer to VTL-10, "Removal and Installation".
NO >> Repair harness or connector. 1, 2 - Ground. : Contin
uity should not exist.
3 - 18 : Continuity should exist.
3 - Ground : Continuity should not exist.
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Revision: December 20092009 QX56

INTAKE SENSORHAC-87
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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INTAKE SENSOR
System DescriptionINFOID:0000000003775382
COMPONENT DESCRIPTION
Intake Sensor
The intake sensor is located on the heater & cooling unit assembly. It
converts temperature of air after if passes through the evaporator
into a resistance value which is then input to the A/C auto amp.
Intake Sensor Diagnosis ProcedureINFOID:0000000003775383
DIAGNOSTIC PROCEDURE FOR INTAKE SENSOR
SYMPTOM: Intake sensor circuit is open or shorted. Using the CON-
SULT-III, DTC B2581 or B2582 is di splayed. Without a CONSULT-III,
code 56 or 57 is indicated on A/C auto amp. as a result of conducting
self-diagnosis.
1.CHECK VOLTAGE BETWEEN INTAKE SENSOR AND GROUND
1. Disconnect intake sensor connector.
2. Turn ignition switch ON.
3. Check voltage between intake sensor harness connector M146 terminal 2 and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> GO TO 4.
2.CHECK CIRCUIT CONTINUITY BETWEEN INTAKE SENSOR AND A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between intake sensor harness connector M146 (B) terminal 1 and A/C auto amp. harness connector M49
(A) terminal 26.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair harness or connector.
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2 - Ground : Approx. 5V
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1 - 26 : Continuity should exist.
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Revision: December 20092009 QX56

HAC-88
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
INTAKE SENSOR
3.CHECK INTAKE SENSOR
Check intake sensor. Refer to HAC-88, "
Intake Sensor Component Inspection".
Is the inspection result normal?
YES >> 1. Replace A/C auto amp. Refer to VTL-7, "Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
NO >> 1. Replace intake sensor. Refer to VTL-11, "
Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
4.CHECK CIRCUIT CONTINUITY BETWEEN INTAKE SENSOR AND A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connector.
3. Check continuity between intake sensor harness connector M146 (B) terminal 2 and A/C auto amp. harness connector M49
(A) terminal 11.
4. Check continuity between intake sensor harness connector M146 (B) terminal 2 and ground.
Is the inspection result normal?
YES >> 1. Replace A/C auto amp. Refer to VTL-7, "Removal and Installation".
2. Go to HAC-23, "
A/C Auto Amp. Self-Diagnosis" and perform self-diagnosis.
NO >> Repair harness or connector.
Intake Sensor Component InspectionINFOID:0000000003775384
COMPONENT INSPECTION
Intake Sensor
After disconnecting intake sensor connector, measure resistance
between terminals 1 and 2 at sensor harness side, using the table
below.
If NG, replace intake sensor. Refer to VTL-11, "
Removal and Installa-
tion".2 - 11
: Continuity should exist.
2 - Ground : Continuity should not exist.
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Temperature °C ( °F) Resistance kΩ
− 15 (5) 209.0
− 10 (14) 160.0
− 5 (23) 123.0
0 (32) 95.8
5 (41) 74.9
10 (50) 58.9
15 (59) 46.7
20 (68) 37.3
25 (77) 30.0
30 (86) 24.2
35 (95) 19.7
40 (104) 16.1
45 (113) 13.2
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Revision: December 20092009 QX56

POWER SUPPLY AND GROUND CIRCUIT FOR CONTROLLER
HAC-89
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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POWER SUPPLY AND GROUND CIRCUIT FOR CONTROLLER
Component DescriptionINFOID:0000000003775385
COMPONENT DESCRIPTION
A/C auto amp.
The A/C auto amp. 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 A/C auto amp. is unitized with control mechanisms. When the
various switches and temperature dials are operated, data is input to
the A/C auto amp.
Self-diagnostic functions are also bu ilt into the A/C auto amp. to pro-
vide quick check of malfunctions in the auto air conditioner system.
Potentio Temperature Control (PTC)
There are two PTCs (driver and passenger) built into the A/C auto
amp. They can be set at an interval of 0.5 °C (1.0 °F) in the 18° C
(60 °F) to 32 °C (90° F) temperature range by rotating the temperature
dial. The set temperature is displayed.
A/C Auto Amp. Com ponent Function CheckINFOID:0000000003775386
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 ambient, 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 HAC-4, "
Operational Check
(Front)".
Can a symptom be duplicated?
YES >> Refer to HAC-3, "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
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Revision: December 20092009 QX56

HAC-90
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
POWER SUPPLY AND GROUND
CIRCUIT FOR CONTROLLER
Check main power supply and ground circuit. Refer to HAC-90, "A/C Auto Amp Power and Ground Diagnosis
Procedure".
Is the inspection result normal?
YES >> System OK.
NO >> Replace A/C auto amp. Refer to VTL-7, "
Removal and Installation".
A/C Auto Amp Power and Ground Diagnosis ProcedureINFOID:0000000003775387
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
1. CHECK POWER SUPPLY CIRCUITS FOR A/C AUTO AMP.
1. Turn ignition switch ON.
2. Check voltage between A/C auto amp. harness connector M49 (B) terminal 15 and M50 (A) terminal 27, and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Check 10A fuses [Nos. 8 and 19, located in the fuse block (J/B)]. Refer to PG-72, "
Terminal
Arrangement".
• If fuses are OK, check harness for open circuit. Repair or replace as necessary.
• If fuses are NG, replace fuse and check harness fo r short circuit. Repair or replace as neces-
sary.
2. CHECK GROUND CIRCUIT FOR A/C AUTO AMP.
1. Turn ignition switch OFF.
2. Disconnect A/C auto amp. connectors.
3. Check continuity between A/C auto amp. harness connector M50 terminal 36 and ground.
Is the inspection result normal?
OK >> Replace A/C auto amp. Refer to VTL-7, "Removal and
Installation".
NG >> Repair harness or connector.
AWIIA0212GB
Terminals Ignition switch position
(+)
(-) OFF ACC ON
A/C auto
amp. con- nector Te r m i n a l N o .
M49 15 GroundApprox. 0V Approx. 0V
Battery
voltage
M50 27 Battery
voltage Battery
voltage Battery
voltage
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36 - Ground : Continuity should exist.
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Revision: December 20092009 QX56