2004 INFINITI QX56 Ins

ATC-124
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
COMPONENT INSPECTION
Water Valve R elay
Check continuity between terminals by supplying 12 volts and
ground to coil side terminals of relay.
WJIA0899E

TROUBLE DIAGNOSIS
ATC-127
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
COMPONENT INSPECTION
Ambient Sensor
After disconnecting ambient sensor connector E1, measure resis-
tance between terminals 2 and 1 at sensor component side, using
the table below.
If NG, replace ambient sensor.
Temperature °C (°F) Resistance kΩ
−15 (5) 12.60
−10 (14) 9.92
−5 (23) 7.80
0 (32) 6.19
5 (41) 4.95
10 (50) 3.99
15 (59) 3.24
20 (68) 2.65
25 (77) 2.19
30 (86) 1.81
35 (95) 1.51
40 (104) 1.27
45 (113) 1.07
WJIA0821E

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
WJIA0825E
WJIA0569E

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-136
AMBIENT SENSOR
Revision: August 20072004 QX56
AMBIENT SENSORPFP:27722
Removal and InstallationEJS002CX
REMOVAL
1. Disconnect the ambient sensor electrical connector.
NOTE:
The ambient sensor is located behind the front bumper, in front
of the condenser.
2. Release the ambient sensor clip and then remove the ambient
sensor.
INSTALLATION
Installation is in the reverse order of removal.
WJIA0819E

IN-VEHICLE SENSOR
ATC-137
C
D
E
F
G
H
I
K
L
MA
B
AT C
Revision: August 20072004 QX56
IN-VEHICLE SENSORPFP:27720
Removal and InstallationEJS002CY
REMOVAL
1. Remove the cluster lid D. Refer to IP-12, "Cluster Lid D" .
2. Remove the two screws and remove the in-vehicle sensor.
INSTALLATION
Installation is in the reverse order of removal.
LJIA0132E

ATC-138
OPTICAL SENSOR
Revision: August 20072004 QX56
OPTICAL SENSORPFP:28576
Removal and InstallationEJS002CZ
The optical sensor is located in the top center of the instrument
panel. Refer to LT- 6 4 , "
Removal and Installation of Optical Sensor" .
WJIA0607E