air condition INFINITI QX4 2005 Factory Service Manual

TROUBLE DIAGNOSIS
ATC-53
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Revision: October 20052005 QX56
Front Air Control Terminals and Reference ValueEJS003XJ
Measure voltage between each terminal and ground by following
Terminals and Reference Value for front air control.
PIN CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUE FOR FRONT AIR CONTROL
WJIA0544E
WJIA0402E
Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
1 B Ground - - 0V
2 Y Sensor power ON - 5V
3 W/G Air mix door motor (Driver) CW ON Clockwise rotation Battery voltage
4 G Air mix door motor (Driver) CCW ON Counterclockwise rotation Battery voltage
5 BR/W Mode door motor CW ON Clockwise rotation Battery voltage
6 P/L Mode door motor CCW ON Counterclockwise rotation Battery voltage
7 O Intake door motor CCW ON Counterclockwise rotation Battery voltage
8 G/B Intake door motor CW ON Clockwise rotation Battery voltage
9 L/B Intake sensor ON - 0 - 5V
10 L/R Fan ON signalON Blower switch OFF 5V
ON Blower switch ON 0V
11 Y/B Rear defroster request ON - Battery voltage
12 W/R Compressor ON signalON A/C switch OFF 5V
ON A/C switch ON 0V
13 G/R Variable blower control ON - 0 - 5V
14 Y/G Power supply for IGN ON - Battery voltage
15 P Sensor ground ON - 0V
16 GR Mode door motor feedback ON - 0 - 5V
17 P Ambient sensor ON - 0 - 5V
18 SB Air mix door motor (Driver) feedback ON - 0 - 5V
19 LG Defroster door motor CW ON Clockwise rotation Battery voltage
20 P/B Defroster door motor CCW ON Counterclockwise rotation Battery voltage
21 V/R Sensor return ON - 0 - 5V

ATC-54
TROUBLE DIAGNOSIS
Revision: October 2005 2005 QX56
22 Y/R Power supply for BAT - - Battery voltage
23 R/L Illumination + ON Park lamps ON Battery voltage
24 BR Illumination - - Park lamps ON
25 LG/B Defroster door motor feedback ON - 0 - 5V
26 R/B Front blower request ONFront blower motor OFF Battery voltage
Front blower motor ON 0V
27 GR/R Air mix door motor (Rear) CW ON Clockwise rotation Battery voltage
28 L/Y Air mix door motor (Rear) CCW ON Counterclockwise rotation Battery voltage
29 W/G Water valve ONWater valve open 0V
Water valve closed Battery voltage
31 W/V Optical sensor (Passenger) ON - 0 - 5V
32 LG/R In-vehicle sensor signal ON - 0 - 5V
33 V Air mix door (Rear) set point ON - 0 - 5V
34 L CAN-H ON - 0 - 5V
35 P CAN-L ON - 0 - 5V
36 G/W Air mix door motor (Passenger) CW ON Clockwise rotation Battery voltage
37 LAir mix door motor (Passenger)
CCWON Counter clockwise rotation Battery voltage
38 W/L Rear blower request ONFront blower motor OFF Battery voltage
Front blower motor ON 0V
39 Y/B Rear select signal ON - 0V - Battery voltage
40 G/O Optical sensor (Driver) ON - 0 - 5V
41 R/WAir mix door motor (Passenger)
feedbackON - 0 - 5V
42 R/Y Air mix door motor (Rear) feedback ON - 0 - 5V
43 BR/Y In-vehicle sensor motor (+) ON - Battery voltage
44 O/B In-vehicle sensor motor (-) ON - 0V Te r m i -
nal No.Wire
colorItemIgnition
switchConditionVoltage (V)
(Approx.)
PIIA2344E

TROUBLE DIAGNOSIS
ATC-59
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Revision: October 20052005 QX56
CHECKING TEMPERATURE INCREASE
1. Rotate temperature control dial clockwise (driver side or passen-
ger side) until 32°C (90°F) is displayed.
2. Check for hot air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for ATC-128, "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 2 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)" or AT C - 7 6 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue with next check.
CHECK A/C SWITCH
1. Press A/C switch when AUTO switch is ON, or in manual mode.
2. A/C switch indicator will turn ON.

Confirm that the compressor clutch engages (sound or visual
inspection).
If NG, go to trouble diagnosis procedure for AT C - 11 5
.
If OK, continue with next check.
CHECKING AUTO MODE
1. Press AUTO switch.
2. Display should indicate AUTO.

If ambient temperature is warm, and selected temperature is
cool, confirm that the compressor clutch engages (sound or
visual inspection). (Discharge air and blower speed will
depend on ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for ATC-61, "
Power Supply
and Ground Circuit for Front Air Control" , then if necessary, trouble
diagnosis procedure for ATC-115, "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in ATC-38, "
How to Perform Trouble
Diagnosis for Quick and Accurate Repair" and perform tests as out-
lined to simulate driving conditions environment. If symptom appears. Refer to AT C - 3 8 , "
How to Perform Trou-
ble Diagnosis for Quick and Accurate Repair" , ATC-38, "SYMPTOM TABLE" and perform applicable trouble
diagnosis procedures.
WJIA1048E
WJIA1049E
WJIA1043E

ATC-60
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Operational Check (Rear)EJS003XM
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear blower control dial to switch position "1". Blower
should operate on low speed.
2. Turn the rear blower control dial counterclockwise to switch
position "2", "3", and "4" until all speeds are checked.
3. Leave blower on MAX speed.
If NG, go to trouble diagnosis procedure for ATC-101, "
Rear Blower
Motor Circuit" .
If OK, continue the check.
CHECKING TEMPERATURE DECREASE
1. Rotate temperature and mode dial fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation if OK, go to
trouble diagnosis procedure for ATC-121, "
Insufficient Cooling" . If
air mix door motor appears to be malfunctioning, go to ATC-79,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue the check.
CHECKING TEMPERATURE INCREASE
1. Rotate temperature and mode dial clockwise.
2. Check for hot air at appropriate discharge air outlets.
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for ATC-128, "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to ATC-79,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue the check.Conditions : Engine running and at normal operating temperature
WJIA1350E
WJIA1069E
WJIA1070E

ATC-62
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
COMPONENT DESCRIPTION
Front Air Control
The front air control 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 front air control is unitized with control mechanisms. When the
various switches and temperature dials are operated, data is input to
the front air control.
Self-diagnostic functions are also built into the front air control to pro-
vide quick check of malfunctions in the auto air conditioner system.
Potentio Temperature Control (PTC)
There are two PTCs (passenger and driver) built into the front air
control. They can be set at an interval of 0.5°C (1.0°F) in the 16°C
(60°F) to 32°C (90°F) temperature range by rotating the temperature
dial. The set temperature is displayed.
DIAGNOSTIC PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
WJIA0544E
WJIA1050E
WJIA0414E

ATC-66
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
COMPONENT DESCRIPTION
Mode Door Motor
The mode door motor is attached to the heater & cooling unit. It
rotates so that air is discharged from the outlet as indicated by the
front air control. Motor rotation is conveyed to a link which activates
the mode door.
DIAGNOSTIC PROCEDURE FOR MODE DOOR MOTOR
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Press the mode switch to the B/L ( ) mode.
3. Check voltage between front air control harness connector M49
terminal 5 and terminal 6 while pressing the mode switch to the
floor ( ) mode.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK MODE DOOR MOTOR CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 5, 6 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
WJIA0587E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M496 5Press
mode
switchBattery
voltage
WJIA1727E
5 - Ground : Continuity should not exist.
6 - Ground : Continuity should not exist.
WJIA1734E

TROUBLE DIAGNOSIS
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Revision: October 20052005 QX56
3. CHECK FRONT AIR CONTROL FOR GROUND AND POWER
1. Press the mode switch to the D/F ( ) mode.
2. Check voltage between front air control harness connector M49
terminal 5 and terminal 6 while pressing the mode switch to the
vent ( ) mode.
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-147, "
FRONT AIR CONTROL" .
4. CHECK MODE DOOR MOTOR AND CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 5 and terminal 6.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK MODE DOOR MOTOR CIRCUITS FOR OPEN
1. Disconnect the mode door motor harness connector.
2. Check continuity between front air control harness connector
M49 terminal 5, 6 and the mode door motor harness connector
terminal 5, 6.
OK or NG
OK >> Replace mode door motor. Refer to ATC-165, "Removal
and Installation" .
NG >> Repair or replace harness as necessary.
6. CHECK FRONT AIR CONTROL FOR PBR POWER AND GROUND
1. Reconnect front air control harness connector.
2. Turn ignition switch ON.
3. Check voltage between front air control harness connector M49
terminal 2 and terminal 15.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
ConnectorTerminals
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M495 6Press
mode
switchBattery
voltage
WJIA1742E
Continuity should exist.
WJIA1728E
5 - 5 : Continuity should exist.
6 - 6 : Continuity should exist.
LJIA0027E
ConnectorTe r m i n a l s
Voltage
(Approx.)
(+) (-)
Front air control: M49 2 15 5V
WJIA1729E

ATC-72
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
COMPONENT DESCRIPTION
Air Mix Door Motors
The driver and front passenger air mix door motors are attached to
the front heater & cooling unit. The rear air mix door motor is
attached to the rear heater & cooling unit. These motors rotate so
that the air mix door is opened or closed to a position set by the front
(or rear) air control. Motor rotation is then conveyed through a shaft
and the air mix door position is then fed back to the front air control
by the PBR built into the air mix door motors.
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (DRIVER)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32°C (90°F).
3. Check voltage between front air control harness connector M49
terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16°C (60°F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
WJIA1876E
WJIA1877E
WJIA1245E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M493 4Rotate temp
control dialBattery
voltage
WJIA1735E

TROUBLE DIAGNOSIS
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Revision: October 20052005 QX56
2. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 3, 4 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (driver) to 32°C (90°F).
3. Check voltage between front air control harness connector M49
terminal 3 and terminal 4 while rotating temperature control dial
(driver) to 16°C (60°F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-147, "
FRONT AIR CONTROL" .
4. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M49 terminal 3 and terminal 4.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. CHECK AIR MIX DOOR MOTOR (DRIVER) CIRCUITS FOR OPEN
1. Disconnect the air mix door motor (driver) harness connector.
2. Check continuity between front air control harness connector
M49 terminal 3, 4 and the air mix door motor (driver) harness
connector M147 terminal 1, 6.
OK or NG
OK >> Replace air mix door motor (driver). Refer to ATC-166,
"FRONT AIR MIX DOOR MOTOR (DRIVER)" .
NG >> Repair or replace harness as necessary.3 - Ground : Continuity should not exist.
4 - Ground : Continuity should not exist.
WJIA1736E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M494 3Rotate temp
control dialBattery
voltage
WJIA1737E
Continuity should exist.
WJIA1738E
3 - 1 : Continuity should exist.
4 - 6 : Continuity should exist.
WJIA0588E

ATC-76
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR (PASSENGER)
1. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 32°C (90°F).
3. Check voltage between front air control harness connector M50
terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 16°C (60°F).
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. CHECK AIR MIX DOOR MOTOR (PASSENGER) CIRCUITS FOR SHORT TO GROUND
1. Turn ignition switch OFF.
2. Disconnect the front air control harness connector.
3. Check continuity between front air control harness connector
M50 terminal 36, 37 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair or replace harness as necessary.
3. CHECK FRONT AIR CONTROL FOR POWER AND GROUND
1. Turn ignition switch ON.
2. Rotate temperature control dial (passenger) to 16°C (60°F).
3. Check voltage between front air control harness connector M50
terminal 36 and terminal 37 while rotating temperature control
dial (passenger) to 32°C (90°F).
OK or NG
OK >> GO TO 4.
NG >> Replace front air control. Refer to ATC-147, "
FRONT AIR CONTROL" .
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M5037 36Rotate temp
control dialBattery
voltage
WJIA1740E
36 - Ground : Continuity should not exist.
37 - Ground : Continuity should not exist.
WJIA1741E
ConnectorTe r m i n a l s
Condition Voltage
(Approx.)
(+) (-)
Front air control:
M5036 37Rotate temp
control dialBattery
voltage
WJIA1778E