2008 INFINITI QX56 fl sensor

SELF-DIAGNOSIS FUNCTIONHAC-23
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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• Press the “BACK” switch and the “UP” switch within 10 seconds after turning the ignition switch from OFF to ACC and hold them for
3 seconds or more. Then the buzzer sounds, all indicators of the
preset switch illuminate, and the self-diagnosis mode starts.
• The continuity of each switch and control dials (A/C and AV switch assembly only) at the ON position can be checked by pressing
each switch and turning each control dial. The buzzer sounds and
LED’s will illuminate if the switch is normal.
Finishing self-diagnosis mode
Self-diagnosis mode is canceled when turning the ignition switch OFF.
A/C System Self-Diagnosis Code ChartINFOID:0000000001679781
SELF-DIAGNOSTIC CODE CHART
AWIIA0171GB
Code No. Reference page
03 Battery voltage out of range CHG-11, "
Inspection Procedure"
30 In-vehicle sensor circuit out of range (low)
HAC-81, "In-Vehicle Sensor Diagnosis Procedure"31 In-vehicle sensor circuit out of range (high)
40 Ambient sensor circuit shortHAC-78, "
Ambient Sensor Diagnosis Procedure"41 Ambient sensor circuit open
50 Optical sensor (Driver) circuit open or shortHAC-84, "
Optical Sensor Diagnosis Procedure"52 Optical sensor (Passenger) circuit open or short
56 Intake sensor circuit shortHAC-86, "
Intake Sensor Diagnosis Procedure"57 Intake sensor circuit open
80 CAN bus faultLAN-14, "
Trouble Diagnosis Flow Chart"
Revision: March 2010 2008 QX56

HAC-24
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
MODE DOOR MOTOR
COMPONENT DIAGNOSIS
MODE DOOR MOTOR
System DescriptionINFOID:0000000001679782
SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:
• A/C auto amp.
• A/C and AV switch assembly
• Mode door motor (front)
• PBR (built into mode door motor)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
The mode door position (vent, B/L, foot
, D/F, and defrost) is set by the A/C auto amp. by means of the mode
door motor (front). When a mode door position is selected on the A/C auto amp., voltage is applied to one cir-
cuit of the mode door motor (front) while ground is applied to the other circuit, causing the mode door motor
(front) to rotate. The direction of rotation is determi ned by which circuit has voltage applied to it, and which one
has ground applied to it. The A/C auto amp. monitors the mode door position by measuring the voltage signal
on the PBR circuit.
In AUTO mode the mode door position is set by the A/C auto amp. which determines the proper position
based on inputs from the in-vehicle sensor, ambient sensor , optical sensor, intake sensor, and the temperature
selected by the driver or passenger.
Mode Door Control Specification
COMPONENT DESCRIPTION
Mode Door Motor (Front)
AWIIA0092GB
AWIIA0093GB
Revision: March 2010 2008 QX56

HAC-30
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
AIR MIX DOOR MOTOR
AIR MIX DOOR MOTOR
System DescriptionINFOID:0000000001679785
SYSTEM DESCRIPTION
SYMPTOM:• Discharge air temperature does not change.
• Air mix door motor does not operate.
SYSTEM DESCRIPTION
Component Parts
Air mix door control system components are:• A/C auto amp.
• A/C and AV switch assembly
• Air mix door motors (driver, passenger, and rear)
• PBR (built-into air mix door motors)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
The A/C auto amp. receives data from the temperature
selected by the driver side, passenger side, and rear.
The A/C auto amp. then applies a voltage to one circuit of the appropriate air mix door motor, while ground is
applied to the other circuit, causing the appropriate air mix door motor to rotate. The direction of rotation is
determined by which circuit has voltage applied to it , and which one has ground applied to it. The A/C auto
amp. monitors the air mix door positions by measur ing the voltage signal on the PBR circuits of each door.
In AUTO mode the air mix, intake, mode door, and defrost door positions are set by the A/C auto amp. which
determines the proper position based on inputs from the in-vehicle sensor, ambient sensor, optical sensor,
intake sensor, and the temperature selected by the driver and front and rear passengers.
Subsequently, HOT/COLD or DEFROST/VENT or FR ESH/RECIRCULATION operation is selected. The new
door position data is returned to the A/C auto amp.
AWIIA0106GB
Revision: March 2010 2008 QX56

HAC-40
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
INTAKE DOOR MOTOR
INTAKE DOOR MOTOR
System DescriptionINFOID:0000000001679789
SYSTEM DESCRIPTION
SYMTOM:• Intake door motor does not operate normally.
• Intake door does not change.
SYSTEM DESCRIPTION
Component Parts
Intake door control system components are:• A/C auto amp.
• A/C and AV switch assembly
• Intake door motor (PRB built into the intake door motor)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
The intake door control determines the intake door position based on the position of the recirculation switch.
When the recirculation switch is depressed the intake
door motor rotates closing off the fresh air inlet and
recirculating the cabin air. If the recirculation switch is depressed again, the intake door motor rotates in the
opposite direction, again allowing fresh air into the cabin.
In the AUTO mode, the A/C auto amp. determines the intake door position based on the ambient temperature,
the intake air temperature and the in-vehicle temperature. When the DEF, D/F, FLOOR or OFF switches are
pushed, the A/C auto amp. sets the intake door at the fresh position.
Intake Door Control Specification
AWIIA0144GB
AWIIA0145GB
Revision: March 2010 2008 QX56

HAC-44
< COMPONENT DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
DEFROSTER DOOR MOTOR CIRCUIT
DEFROSTER DOOR
MOTOR CIRCUIT
System DescriptionINFOID:0000000001679792
SYSTEM DESCRIPTION
Component Parts
Defroster door control system components are:• A/C auto amp.
• A/C and AV switch assembly
• Defroster door motor
• PBR (Built into defroster door motor)
• In-vehicle sensor
• Ambient sensor
• Optical sensor
• Intake sensor
System Operation
The A/C auto amp. determines defroster door position bas ed on the position of the defroster switch. When the
defroster switch is depressed, the defroster door motor rotates directing air to the defroster ducts. When any
mode other than defroster is selected, the defroster moto r rotates in the opposite direction closing off air flow
to the defroster ducts.
In the AUTO mode, the A/C auto amp. determines def roster door position based on the ambient temperature,
the intake air temperature and the in-vehicle temperature.
COMPONENT DESCRIPTION
Defroster door motor
The defroster door motor is attached to the front heater & cooling
unit assembly. The A/C auto amp. sends a voltage to rotate to the
defroster door directing the air flow either to the defroster ducts, or to
the floor ducts, depending on which way the voltage and ground are
applied to the motor leads. Motor rotation is conveyed to a lever
which activates the defroster door.
AWIIA0151GB
WJIA0592E
Revision: March 2010 2008 QX56

BLOWER MOTOR CONTROL SYSTEMHAC-49
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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BLOWER MOTOR CONTROL SYSTEM
System DescriptionINFOID:0000000001679795
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).
AWIIA0173GB
Revision: March 2010 2008 QX56

BLOWER MOTOR CONTROL SYSTEMHAC-51
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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YES >> Refer to HAC-23, "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-22, "
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-51, "
Front Blower Motor Diagnosis Procedure".
7.CHECK ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT
Check engine coolant temperature sensor circuit. Refer to EC-125, "
Diagnosis Procedure".
Is the inspection results normal?
YES >> GO TO 8.
NO >> Replace engine 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:0000000001679797
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
AWIIA0174GB
Revision: March 2010 2008 QX56

MAGNET CLUTCHHAC-71
< COMPONENT DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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MAGNET CLUTCH
System DescriptionINFOID:0000000001679808
SYSTEM DESCRIPTION
The A/C auto amp. controls compressor operation based on ambient and intake temperature and a signal
from ECM.
Low Temperature Protection Control
The A/C auto amp. will turn the compressor ON or OFF as determined by a signal detected by the intake sen-
sor and the ambient sensor.
When intake air temperature is higher than the preset value, the compressor turns ON. The compressor turns
OFF when intake air temperature is lower than the pres et value. That preset value is dependent on the ambi-
ent temperature, refer to the following table.
Magnet Clutch Componen t Function CheckINFOID:0000000001679809
INSPECTION FLOW
1.CONFIRM SYMPTOM BY PERFORMING O PERATIONAL CHECK - MAGNET CLUTCH
1. Turn ignition switch ON.
2. Press the A/C switch.
3. Press vent switch ( ).
4. Display shows , A/C. Confirm that the compress or clutch engages (sound or visual inspection). (Dis-
charge air and blower speed will depend on ambient, in-vehicle and set temperatures.)
Can the symptom be duplicated?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK 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 >> System OK.
3.CHECK FOR SERVICE BULLETINS
Check for any service bulletins.
>> GO TO 4.
4.PERFORM SELF-DIAGNOSIS
Perform self-diagnosis to check for any codes. Refer to HAC-22, "
A/C Auto Amp. Self-Diagnosis".
Are any self-diagnosis codes present?
YES >> Refer to HAC-23, "A/C System Self-Diagnosis Code Chart".
NO >> GO TO 5.
5.CHECK AMBIENT SENSOR
Check and verify ambient s ensor circuit. Refer to HAC-78, "
Ambient Sensor Diagnosis Procedure".
Ambient temperature ° C (°F) Compressor ON intake temperature °C ( °F) Compressor OFF intake temperature °C ( °F)
0 (32) 5.5 (42) 5.0 (41)
10 (50) 5.5 (42) 5.0 (41)
20 (68) 5.5 (42) 5.0 (41)
30 (86) 4.0 (39) 3.5 (38)
40 (104) 3.5 (38) 3.0 (37)
50 (122) 3.5 (38) 3.0 (37)
Revision: March 2010 2008 QX56