Air INFINITI QX56 2004 Factory Service Manual

ATC-128
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
In-vehicle Sensor CircuitEJS002CT
COMPONENT DESCRIPTION
In-vehicle Sensor
The in-vehicle sensor is located on cluster lid D. It converts varia-
tions in temperature of passenger compartment air (drawn in through
the integrated fan) into a value. It is then input into the front air con-
trol.
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WJIA0606E

TROUBLE DIAGNOSIS
ATC-129
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
DIAGNOSTIC PROCEDURE FOR IN-VEHICLE SENSOR
SYMPTOM: In-vehicle sensor circuit is open or shorted. (30 or 31 is
indicated as a result of conducting self-diagnosis.
1. CHECK IN-VEHICLE SENSOR CIRCUIT
Are diagnostic codes 44 or 46 present?
YES or NO
YES >> GO TO 6.
NO >> GO TO 2.
2. CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR AND GROUND
1. Disconnect in-vehicle sensor connector M32.
2. Turn ignition switch ON.
3. Check voltage between in-vehicle sensor harness connector
M32 terminal 4 (LG/R) and ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49.
3. Check continuity between in-vehicle sensor harness connector
M32 terminal 1 (V/R) and front air control harness connector
M49 terminal 21 (V/R).
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK IN-VEHICLE SENSOR
Refer to ATC-131, "
In-vehicle Sensor" .
OK or NG
OK >> 1. Replace front air control. Refer to ATC-135, "FRONT AIR CONTROL" .
2. Go to AT C - 5 3 , "
A/C System Self-diagnosis Function" and perform self-diagnosis.
NG >> 1. Replace in-vehicle sensor. Refer to ATC-137, "
IN-VEHICLE SENSOR" .
2. Go to AT C - 5 3 , "
A/C System Self-diagnosis Function" and perform self-diagnosis.
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4 - Ground : Approx. 5V
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1 - 21 : Continuity should exist.
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ATC-130
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
5. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50.
3. Check continuity between in-vehicle sensor harness connector
M32 terminal 4 (LG/R) and front air control harness connector
M50 terminal 32 (LG/R).
4. Check continuity between in-vehicle sensor harness connector
M32 terminal 4 (LG/R) 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.
6. CHECK CIRCUIT CONTINUITY BETWEEN IN-VEHICLE SENSOR MOTOR AND FRONT AIR CON-
TROL (SELF-DIAGNOSIS CODES 44 OR 46)
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50 and in-vehicle sensor
connector M32.
3. Check continuity between in-vehicle sensor harness connector
M32 terminal 2 (O/B) and 3 (BR/Y) and front air control harness
connector M50 terminal 44 (O/B) and 43 (BR/Y).
4. Check continuity between in-vehicle sensor harness connector
M32 terminal 2 (O/B) and 3 (BR/Y) and ground.
OK or NG
OK >> 1. Replace front air control. Refer to ATC-135, "FRONT AIR CONTROL" .
2. Go to ATC-53, "
A/C System Self-diagnosis Function" and perform self-diagnosis.
NG >> Repair harness or connector.4 - 32 : Continuity should exist.
4 - Ground Continuity should not exist.
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2 - 44 : Continuity should exist.
3 - 43 : Continuity should exist.
2, 3 - Ground :Continuity should not exist.
WJIA0824E

TROUBLE DIAGNOSIS
ATC-131
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
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.
Optical Sensor CircuitEJS002CU
COMPONENT DESCRIPTION
The optical sensor is located on the top center of the instrument
panel. 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 front air control.
OPTICAL INPUT PROCESS
The front air control 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 trees 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 the 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.
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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ATC-132
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
DIAGNOSTIC PROCEDURE FOR OPTICAL SENSOR
SYMPTOM: Optical sensor circuit is open or shorted. [50 (Driver) or
52 (Passenger) is indicated as a result of conducting self-diagnosis.]
1. CHECK CIRCUIT CONTINUITY BETWEEN OPTICAL SENSOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector M50 and optical sensor
connector M402.
3. Check continuity between optical sensor harness connector
M402 terminal 1 (W/V) and 2 (G/O) and front air control harness
connector M50 terminal 31 (W/V) and 40 (G/O).
4. Check continuity between optical sensor harness connector
M402 terminal 1 (W/V) and 2 (G/O) and ground.
OK or NG
OK >> GO TO 2.
NG >> Repair harness or connector.
2. CHECK CIRCUIT CONTINUITY BETWEEN OPTICAL SENSOR AND BCM
1. Disconnect BCM connector M18.
2. Check continuity between optical sensor harness connector
M402 terminal 3 (P) and BCM harness connector M18 terminal
18 (P).
3. Check continuity between optical sensor harness connector
M402 terminal 3 (P) and ground.
OK or NG
OK >> Replace optical sensor. Refer to ATC-138, "OPTICAL SENSOR" .
NG >> Repair harness or connector.
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1 - 31 : Continuity should exist.
2 - 40 : Continuity should exist.
1, 2 - Ground. : Continuity should not exist.
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3 - 18 : Continuity should exist.
3 - Ground : Continuity should not exist.
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TROUBLE DIAGNOSIS
ATC-133
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
Intake Sensor CircuitEJS002CV
COMPONENT DESCRIPTION
Intake Sensor
The intake sensor is located on the front heater & cooling unit. It con-
verts temperature of air after it passes through the evaporator into a
resistance value which is then input to the front air control.
DIAGNOSTIC PROCEDURE FOR INTAKE SENSOR
SYMPTOM: Intake sensor circuit is open or shorted. (56 or 57 is indi-
cated as a result of conducting self-diagnosis).
1. CHECK VOLTAGE BETWEEN INTAKE SENSOR AND GROUND
1. Disconnect intake sensor connector M146.
2. Turn ignition switch ON.
3. Check voltage between intake sensor harness connector M146
terminal 2 (L/B) and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 4.
2. 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 1 (V/R) and front air control harness connector
M49 terminal 21 (V/R).
OK or NG
OK >> GO TO 3.
NG >> Repair harness or connector.
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2 - Ground : Approx. 5V
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1 - 21 : Continuity should exist.
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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.
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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
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.
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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.
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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" .
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