2004 INFINITI QX56 Air

ATC-134
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
3. CHECK INTAKE SENSOR
Refer to ATC-134, "
Intake Sensor" .
OK or NG
OK >> 1. Replace front air control. Refer to ATC-135, "FRONT AIR CONTROL" .
2. Go to self-diagnosis ATC-53, "
A/C System Self-diagnosis Function" and perform self-diagno-
sis.
NG >> 1. Replace intake sensor. Refer to ATC-139, "
INTAKE SENSOR" .
2. Go to self-diagnosis ATC-53, "
A/C System Self-diagnosis Function" and perform self-diagno-
sis.
4. CHECK CIRCUIT CONTINUITY BETWEEN INTAKE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between intake sensor harness connector
M146 terminal 2 (L/B) and front air control harness connector
M49 terminal 9 (L/B).
4. Check continuity between intake sensor harness connector
M146 terminal 2 (L/B) and ground.
OK or NG
OK >> 1. Replace front air control. Refer to ATC-135, "FRONT AIR CONTROL" .
2. Go to self-diagnosis ATC-53, "
A/C System Self-diagnosis Function" and perform self-diagno-
sis.
NG >> Repair harness or connector.
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.2 - 9 : Continuity should exist.
2 - Ground : Continuity should not exist.
WJIA0831E
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
WJIA0832E

CONTROL UNIT
ATC-135
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
CONTROL UNITPFP:27500
Removal and InstallationEJS002CW
FRONT AIR CONTROL
Removal
1. Remove the five control knobs from the front air control unit.
2. Remove the cluster lid C. Refer to IP-12, "
Cluster Lid C" .
3. Remove the four screws securing the front air control unit to
cluster lid C.
4. Remove the front air control unit.
Installation
Installation is in the reverse order of removal.
REAR AIR CONTROL
Removal
1. Remove the overhead console from the headliner. Refer to EI-37, "HEADLINING" .
2. Remove the four screws and remove the rear air control.
Installation
Installation is in the reverse order of removal.
LJIA0130E
LJIA0131E

ATC-142
IN-CABIN MICROFILTER
Revision: August 20072004 QX56
IN-CABIN MICROFILTERPFP:27277
Removal and InstallationEJS002D3
FUNCTION
The air inside the passenger compartment is filtered by the in-cabin
microfilters when the heater or A/C controls are set on either the
recirculation or fresh mode. The two in-cabin microfilters are located
in the front heater and cooling unit assembly. The rear heater and
cooling unit assembly only draws in air from the passenger compart-
ment to recirculate into the passenger compartment, so the rear
heater and cooling unit assembly is not equipped with in-cabin
microfilters.
REPLACEMENT TIMING
Replacement of the two in-cabin microfilters is recommended on a regular interval depending on the driving
conditions. Refer to MA-6, "
PERIODIC MAINTENANCE" . It may also be necessary to replace the two in-
cabin microfilters as part of a component replacement if the in-cabin microfilters are damaged.
REPLACEMENT PROCEDURE
1. Remove the two lower glove box hinge pins to remove the glove
box from the instrument panel and let it hang from the cord.
2. Remove the screw and remove the in-cabin microfilter cover.
3. Remove the in-cabin microfilters from the front heater and cool-
ing unit assembly housing.
4. Insert the first new in-cabin microfilter into the front heater and
cooling unit assembly housing and slide it over to the right.
Insert the second new in-cabin microfilter into the front heater
and cooling unit assembly housing.
NOTE:
The in-cabin microfilters are marked with air flow arrows. The
end of the microfilter with the arrow should face the rear of the
vehicle. The arrows should point downward.
LJIA0012E
WLIA0027E
LJIA0134E
LJIA0148E

ATC-146
HEATER & COOLING UNIT ASSEMBLY
Revision: August 20072004 QX56
4. Remove the exhaust system. Refer to EX-3, "Removal and Installation" .
5. Disconnect the front heater hoses from the front heater core.
6. Disconnect the high/low pressure pipes from the front expansion valve.
7. Move the two front seats to the rearmost position on the seat track.
8. Remove the instrument panel and console panel. Refer to IP-10, "
INSTRUMENT PANEL ASSEMBLY" .
9. Remove the steering column. Refer to PS-10, "
Removal and Installation" .
10. Disconnect the instrument panel wire harness at the RH and LH in-line connector brackets, and the fuse
block (J/B) electrical connectors. Refer to PG-40, "
Harness Layout" .
11. Disconnect the steering member from each side of the vehicle body.
12. Remove the front heater and cooling unit assembly with it attached to the steering member, from the vehi-
cle.
CAUTION:
Use care not to damage the seats and interior trim panels when removing the front heater and
cooling unit assembly with it attached to the steering member.
13. Remove the front heater and cooling unit assembly from the steering member.
Installation
Installation is in the reverse order of removal.
CAUTION:

Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply
compressor oil to it when installing it.

After charging the refrigerant, check for leaks.
NOTE:

Fill the engine cooling system with the specified coolant mixture. Refer to MA-13, "REFILLING ENGINE
COOLANT" .

Recharge the A/C system. Refer to ATC-162, "Evacuating System and Charging Refrigerant" .
REAR HEATER AND COOLING UNIT ASSEMBLY
Removal
1. Discharge the refrigerant from the A/C system. Refer to ATC-162, "Discharging Refrigerant" .
2. Drain the coolant from the engine cooling system. Refer to MA-12, "
DRAINING ENGINE COOLANT" .
3. Disconnect the rear heater core hoses from the rear heater core.
4. Disconnect the rear A/C pipes from the rear expansion valve.
5. Remove the rear RH interior trim panel. Refer to EI-34,
"Removal and Installation" .
6. Disconnect the following electrical connectors:

Rear blower motor

Rear blower motor resistor

Rear air mix door motor
7. Disconnect the ducts from the rear heater and cooling unit
assembly.
8. Remove the rear heater and cooling unit assembly.
Installation
Installation is in the reverse order of removal.
CAUTION:

Replace the O-ring of the low-pressure pipe and high-pressure pipe with a new one, and apply
compressor oil to it when installing it.

After charging the refrigerant, check for leaks.
NOTE:

Fill the engine cooling system with the specified coolant mixture. Refer to MA-13, "REFILLING ENGINE
COOLANT" .

Recharge the A/C system. Refer to ATC-162, "Evacuating System and Charging Refrigerant" .
LJIA0021E

ATC-150
DEFROSTER DOOR MOTOR
Revision: August 20072004 QX56
DEFROSTER DOOR MOTORPFP:27733
Removal and InstallationEJS002D8
Defroster Door Motor - Front Heater and Cooling Unit Assembly
REMOVAL
1. Remove the front heater and cooling unit assembly. Refer to ATC-145, "FRONT HEATER AND COOLING
UNIT ASSEMBLY" .
2. Remove the steering member from the front heater and cooling unit assembly.
3. Disconnect the defroster door motor electrical connector.
4. Remove the three screws and remove the defroster door motor.
INSTALLATION
Installation is in the reverse order of removal.
LJIA0139E
1. Front heater and cooling unit assembly 2. Intake door motor 3. Air mix door motor (driver)
4. Variable blower control 5. Air mix door motor (passenger) 6. Mode door motor
7. Defroster door motor

INTAKE DOOR MOTOR
ATC-151
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
INTAKE DOOR MOTORPFP:27730
Removal and InstallationEJS002D9
Intake Door Motor - Front Heater and Cooling Unit Assembly
REMOVAL
1. Remove the front heater and cooling unit assembly. Refer to ATC-145, "FRONT HEATER AND COOLING
UNIT ASSEMBLY" .
2. Remove the steering member from the front heater and cooling unit assembly.
3. Disconnect the intake door motor electrical connector.
4. Remove the three screws and remove the intake door motor.
INSTALLATION
Installation is in the reverse order of removal.
LJIA0139E
1. Front heater and cooling unit assembly 2. Intake door motor 3. Air mix door motor (driver)
4. Variable blower control 5. Air mix door motor (passenger) 6. Mode door motor
7. Defroster door motor

ATC-152
MODE DOOR MOTOR
Revision: August 20072004 QX56
MODE DOOR MOTORPFP:27731
Removal and InstallationEJS002DA
Mode Door Motor - Front Heater and Cooling Unit Assembly
REMOVAL
1. Remove the front heater and cooling unit assembly. Refer to ATC-145, "FRONT HEATER AND COOLING
UNIT ASSEMBLY" .
2. Remove the steering member from the front heater and cooling unit assembly.
3. Disconnect the mode door motor electrical connector.
4. Remove the two screws and remove the mode door motor.
INSTALLATION
Installation is in the reverse order of removal.
LJIA0139E
1. Front heater and cooling unit assembly 2. Intake door motor 3. Air mix door motor (driver)
4. Variable blower control 5. Air mix door motor (passenger) 6. Mode door motor
7. Defroster door motor

AIR MIX DOOR MOTOR
ATC-153
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
AIR MIX DOOR MOTOR PFP:27732
ComponentsEJS002DB
Air Mix Door Motors - Front Heater and Cooling Unit Assembly
Removal and InstallationEJS002DC
FRONT AIR MIX DOOR MOTOR (DRIVER)
Removal
1. Remove the front heater and cooling unit assembly. Refer to ATC-145, "FRONT HEATER AND COOLING
UNIT ASSEMBLY" .
2. Remove the steering member from the front heater and cooling unit assembly.
3. Disconnect the air mix door motor electrical connector.
4. Remove the three screws and remove the air mix door motor.
Installation
Installation is in the reverse order of removal.
LJIA0139E
1. Front heater and cooling unit assembly 2. Intake door motor 3. Air mix door motor (driver)
4. Variable blower control 5. Air mix door motor (passenger) 6. Mode door motor
7. Defroster door motor