2004 INFINITI QX56 Ins

ATC-56
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Operational Check (Front)EJS002CB
The purpose of the operational check is to confirm that the system operates properly.
CHECKING MEMORY FUNCTION
1. Set the temperature to 90°F or 32°C.
2. Press OFF switch [hold fan (down) switch down until system
shuts OFF].
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press the AUTO switch.
6. Confirm that the set temperature remains at previous tempera-
ture.
7. Press OFF switch [hold fan (down) switch down until system
shuts OFF].
If NG, go to trouble diagnosis procedure for ATC-121, "
Memory
Function" .
If OK, continue with next check.
CHECKING BLOWER
1. Press fan (up) switch. Blower should operate on low speed. The
front blower speed symbol should have one bar lit (on display).
2. Press fan (up) switch again, and continue checking blower
speed and blower symbol until all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for AT C - 8 5 , "
DIAGNOSTIC
PROCEDURE FOR BLOWER MOTOR" .
If OK, continue with next check.Conditions : Engine running and at normal operating temperature
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TROUBLE DIAGNOSIS
ATC-57
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AT C
Revision: August 20072004 QX56
CHECKING DISCHARGE AIR
1. Press MODE switch four times and then rotate the DEF dial
counterclockwise.
2. Each position indicator should change shape (on display).
3. Confirm that discharge air comes out according to the air distri-
bution table. Refer to AT C - 2 9 , "
Discharge Air Flow" .
Mode door position is checked in the next step.
If NG, go to trouble diagnosis procedure for ATC-63, "
Mode Door
Motor Circuit" .
If OK, continue with next check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at fresh when the DEF or D/F
is selected.
CHECKING RECIRCULATION
1. Press recirculation ( ) switch one time. Recirculation indica-
tor should illuminate.
2. Press recirculation ( ) switch one more time. Fresh ( )
indicator should illuminate.
3. Listen for intake door position change (blower sound should
change slightly).
If NG, go to trouble diagnosis procedure for AT C - 7 6 , "
Intake Door
Motor Circuit" .
If OK, continue with next check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at fresh when the DEF or D/F is selected.
CHECKING TEMPERATURE DECREASE
1. Rotate temperature dial counterclockwise (driver or passenger)
until 18°C (60°F) is displayed.
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 AT C - 11 0 , "
Insufficient Cooling" . If
air mix door motor appears to be malfunctioning, go to AT C - 6 9 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)" or AT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue with next check.
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ATC-58
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
CHECKING TEMPERATURE INCREASE
1. Rotate temperature dial clockwise (driver or passenger) 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-117, "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to ATC-69,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)" or AT C - 7 1 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue with next check.
CHECK A/C SWITCH
1. Press A/C switch.
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 ATC-104, "
Magnet
Clutch Circuit" .
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-60, "
Power Supply
and Ground Circuit for Front Air Control" , then if necessary, trouble
diagnosis procedure for ATC-104, "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction Simulation Tests in AT C - 3 5 , "
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 ATC-35, "
How to Perform Trou-
ble Diagnosis for Quick and Accurate Repair" , AT C - 3 5 , "SYMPTOM TABLE" and perform applicable trouble
diagnosis procedures.
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TROUBLE DIAGNOSIS
ATC-59
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AT C
Revision: August 20072004 QX56
Operational Check (Rear)EJS002CC
The purpose of the operational check is to confirm that the system operates properly.
CHECKING BLOWER
1. Turn the rear fan switch (front) clockwise to "1". The rear blower
should operate on low speed.
2. Turn the rear fan switch (front) clockwise again to switch position
"2", "3", and "4" until all speeds are checked.
3. Leave blower on maximum speed.
If NG, go to trouble diagnosis procedure for AT C - 9 0 , "
Rear Blower
Motor Circuit" .
If OK, continue with next check.
CHECKING TEMPERATURE DECREASE
1. Rotate rear temperature/mode dial (front) fully counterclockwise.
2. Check for cold air at appropriate discharge air outlets (headliner
outlets).
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 0 , "
Insufficient Cooling" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.
CHECKING TEMPERATURE INCREASE
1. Rotate rear temperature/mode dial (front) clockwise.
2. Check for hot air at appropriate discharge air outlets (floor out-
lets).
If NG, listen for sound of air mix door motor operation. If OK, go to
trouble diagnosis procedure for AT C - 11 7 , "
Insufficient Heating" . If
air mix door motor appears to be malfunctioning, go to AT C - 7 3 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(REAR)" .
If OK, continue with next check.Conditions : Engine running and at normal operating temperature
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ATC-60
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Power Supply and Ground Circuit for Front Air ControlEJ S00 2CD
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
*1AT C - 6 0 , "Power Supply and Ground
Circuit for Front Air Control"
*2ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)"
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TROUBLE DIAGNOSIS
ATC-63
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AT C
Revision: August 20072004 QX56
Mode Door Motor CircuitEJS002CE
SYMPTOM:

Air outlet does not change.

Mode door motor does not operate normally.
INSPECTION FLOW
*1ATC-29, "Discharge Air Flow"*2AT C - 5 6 , "Operational Check
(Front)"
*3AT C - 5 3 , "A/C System Self-diagnosis
Function"
*4ATC-55, "SELF-DIAGNOSIS CODE
CHART"
*5AT C - 6 5 , "DIAGNOSTIC PROCE-
DURE FOR MODE DOOR
MOTOR"
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TROUBLE DIAGNOSIS
ATC-65
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AT C
Revision: August 20072004 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 RESULT FROM FRONT AIR CONTROL SELF-DIAGNOSIS
Self-diagnosis code 92 is present. Refer to ATC-53, "
A/C System Self-diagnosis Function" .
YES or NO
YES >> GO TO 2.
NO >> GO TO 3.
2. CHECK POWER SUPPLY AND GROUND CIRCUITS FOR MODE DOOR MOTOR
1. Turn ignition switch OFF.
2. Disconnect front air control connector M49 and mode door
motor connector M142.
3. Check continuity between front air control harness connector
M49 terminal 5 (BR/W) and mode door motor connector M142
terminal 5 (BR/W) and between front air control harness con-
nector M49 terminal 6 (P/L) and mode door motor connector
M142 terminal 6 (P/L).
OK or NG
OK >> Replace mode door motor. Refer to ATC-152, "Removal and Installation" .
NG >> Repair or replace harness as necessary.
3. CHECK PBR REFERENCE SIGNAL VOLTAGE
1. Disconnect mode door motor connector M142.
2. Turn ignition switch ON.
3. Check voltage between mode door motor harness connector
M142 terminal 3 (Y) and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
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5 - 5 : Continuity should exist.
6 - 6 : Continuity should exist.
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3 - Ground : Approx. 5V
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TROUBLE DIAGNOSIS
ATC-67
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AT C
Revision: August 20072004 QX56
Air Mix Door Motor CircuitEJS002CF
SYMPTOM:

Discharge air temperature does not change.

Air mix door motor does not operate.
INSPECTION FLOW
*1ATC-56, "Operational Check (Front)"
or AT C - 5 9 , "
Operational Check
(Rear)"
*2AT C - 5 3 , "A/C System Self-diagno-
sis Function"
*3AT C - 5 5 , "SELF-DIAGNOSIS CODE
CHART"
*4ATC-69, "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
*5AT C - 7 1 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
*6AT C - 7 3 , "DIAGNOSTIC PROCE-
DURE FOR AIR MIX DOOR
MOTOR (REAR)"
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