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ATC-56
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
A/C System Self-diagnosis FunctionEJS003XK
DESCRIPTION
The self-diagnostic system diagnoses sensors, door motors, blower motor, etc. Refer to applicable sections
(items) for details. Fault codes (if any are present) will be displayed in the ambient temperature display area.
Refer to AT C - 5 7 , "
SELF-DIAGNOSIS CODE CHART" .
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TROUBLE DIAGNOSISATC-57
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SELF-DIAGNOSIS CODE CHART
Code No.Reference page
02 EE changed by calibration ATC-144, "
FRONT AIR CONTROL"
03 Battery voltage out of rangeSC-4, "BATTERY"
12 Air mix door motor (Passenger) circuit failureAT C - 7 6 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (PASSENGER)"
20 BCM not responding to A/C requestAT C - 11 6 , "DIAGNOSTIC PROCEDURE FOR MAGNET
CLUTCH"
21 BCM not responding to rear defroster request
GW-74, "REAR WINDOW DEFOGGER"
22 Air mix door motor (Driver) circuit failureAT C - 7 2 , "DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (DRIVER)"
30 In-vehicle sensor circuit out of range (low)
ATC-137, "In-vehicle Sensor Circuit"31 In-vehicle sensor circuit out of range (high)
38 Air mix door motor (rear) circuit failureAT C - 7 9 , "
DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR
MOTOR (REAR)"
40 Ambient sensor circuit short
ATC-134, "Ambient Sensor Circuit"41 Ambient sensor circuit open
44 In-vehicle sensor motor circuit openATC-142, "
Intake Sensor Circuit"46 In-vehicle sensor motor circuit short
50 Optical sensor (Driver) circuit open or shortATC-140, "
Optical Sensor Circuit"52 Optical sensor (Passenger) circuit open or short
56 Intake sensor circuit shortATC-142, "
Intake Sensor Circuit"57 Intake sensor circuit open
62 Defroster door motor circuit failureAT C - 8 7 , "
Defroster Door Motor Circuit"
80 CAN bus faultLAN-26, "CAN COMMUNICATION"
82 Intake door motor (driver) circuit malfunctionAT C - 8 5 , "DIAGNOSTIC PROCEDURE FOR INTAKE DOOR
MOTOR"
90 Stuck button
ATC-144, "FRONT AIR CONTROL"
92 Mode door motor circuit failureAT C - 6 4 , "Mode Door Motor Circuit"
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ATC-58
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Operational Check (Front)EJS003XL
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. Turn front blower control dial counterclockwise 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 temperature.
7. Turn front blower control counterclockwise until system shuts OFF.
If NG, go to trouble diagnosis procedure for ATC-131, "
Memory Function" .
If OK, continue with next check.
CHECKING BLOWER
1. Turn front blower control clockwise, blower should operate on low speed. The blower symbol should have one blade lit (on display).
2. Turn the front blower control dial again, and continue checking blower speed and blower symbol until all speeds are checked.
3. Leave blower on MAX speed.
If NG, go to trouble diagnosis procedure for AT C - 9 5 , "
DIAGNOSTIC PROCEDURE FOR BLOWER
MOTOR"AT C - 9 5 , "DIAGNOSTIC PROCEDURE FOR BLOWER MOTOR" .
If OK, continue with next check.
CHECKING DISCHARGE AIR
1. Press MODE switch four times and the DEF ( ) switch.
2. Each position indicator should change shape (on display).
3. Confirm that discharge air comes out according to the air distribution table. Refer to AT C - 3 0 , "
Discharge
Air Flow" .
Mode door position is checked in the next step.
If NG, go to trouble diagnosis procedure for AT C - 6 4 , "
Mode Door Motor Circuit" .
If OK, continue the 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 (, ONLY)
1. Press recirculation ( ) switch one time. Recirculation indicator should illuminate.
2. Press recirculation ( ) switch one more time. Recirculation indicator should go off.
3. Listen for intake door position change (blower sound should change slightly).
If NG, go to trouble diagnosis procedure for AT C - 8 3 , "
Intake Door Motor Circuit" .
If OK, continue the 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. REC ( ) is not allowed in DEF ( ) D/F ( ) or FOOT ( ).
CHECKING TEMPERATURE DECREASE
1. Rotate temperature control dial (driver side or passenger side) counterclockwise until 16 °C (60 °F) is dis-
played.
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 AT C - 7 2 , "DIAGNOSTIC PRO-
CEDURE FOR AIR MIX DOOR MOTOR (DRIVER)" or AT C - 7 6 , "DIAGNOSTIC PROCEDURE FOR AIR MIX
DOOR MOTOR (PASSENGER)" .
If OK, continue the check. Conditions : Engine running and at normal operating temperature
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TROUBLE DIAGNOSISATC-59
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CHECKING TEMPERATURE INCREASE
1. Rotate temperature control dial clockwise (driver side or passenger 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 PRO-
CEDURE 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).
NOTE:
If current mode setting is DEF or D/F, compressor clutch may already be engaged.
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-vehi-
cle, and set temperatures.)
If NG, go to trouble diagnosis procedure for AT C - 6 1 , "
Power Supply and Ground Circuit for Front Air Control" ,
then if necessary, trouble diagnosis procedure for AT C - 11 5 , "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go to malfunction Simulation Tests in AT C -
39, "How to Perform Trouble Diagnosis for Quick and Accurate Repair" and perform tests as outlined to simu-
late driving conditions environment. If symptom appears. Refer to AT C - 3 9 , "
How to Perform Trouble Diagnosis
for Quick and Accurate Repair" , AT C - 3 9 , "SYMPTOM TABLE" and perform applicable trouble diagnosis pro-
cedures.
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ATC-60
TROUBLE DIAGNOSIS
Revision: November 20092006 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 AT C - 7 9 , "DIAGNOSTIC PRO-
CEDURE 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 AT C - 7 9 , "DIAGNOSTIC PRO-
CEDURE FOR AIR MIX DOOR MOTOR (REAR)" .
If OK, continue the check. Conditions : Engine running and at normal operating temperature
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TROUBLE DIAGNOSISATC-61
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Revision: November 2009 2006 QX56
Power Supply and Ground Circuit for Front Air ControlEJS003XN
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
*1AT C - 6 1 , "Power Supply and Ground
Circuit for Front Air Control". *2
ATC-58, "
Operational Check (Front)"
or AT C - 6 0 , "
Operational Check
(Rear)" .
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ATC-62
TROUBLE DIAGNOSIS
Revision: November 20092006 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.
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TROUBLE DIAGNOSISATC-63
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1. CHECK POWER SUPPLY CIRCUITS FOR FRONT AIR CONTROL
1. Disconnect front air control connector.
2. Check voltage between front air control harness connector M49 terminals 14 and 22, and ground.
OK or NG
OK >> GO TO 2.
NG >> Check 10A fuses [Nos. 8 and 19, located in the fuse block (J/B)]. Refer to PG-76, "
FUSE BLOCK-
JUNCTION BOX (J/B)" .
If fuses are OK, check harness for open circuit. Repair or replace as necessary.
If fuses are NG, replace fuse and check harness for short circuit. Repair or replace as neces-
sary.
2. CHECK GROUND CIRCUIT FOR FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Check continuity between front air control harness connector M49 terminal 1 and ground.
OK or NG
OK >> Replace front air control. Refer to ATC-144, "FRONT
AIR CONTROL" .
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON
Front air
control
connector Terminal No.
M49 14 GroundApprox. 0V Approx. 0V
Battery
voltage
M49 22 Battery
voltage Battery
voltage Battery
voltage
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1 - Ground : Continuity should exist.
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