Page 393 of 3171

TROUBLE DIAGNOSIS
ATC-59
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F
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MA
B
AT C
CHECKING TEMPERATURE INCREASE
1. Rotate temperature control dial clockwise (driver 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 forATC-100, "
Insufficient Heating".If
air mix door motor appears to be malfunctioning, go toAT C - 7 1 ,
"DIAGNOSTIC PROCEDURE FOR AIR MIX DOOR MOTOR
(DRIVER)".
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.
lConfirm that the compressor clutch engages (sound or visual
inspection).
If NG, go to trouble diagnosis procedure forAT C - 8 7 , "
Magnet Clutch
Circuit".
If OK, continue with next check.
CHECKING AUTO MODE
1. Press AUTO switch.
2. Display should indicate AUTO.
lIf 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 forAT C - 6 0 , "
Power Supply
and Ground Circuit for Front Air Control", then if necessary, trouble
diagnosis procedure forAT C - 8 7 , "
Magnet Clutch Circuit".
If all operational checks are OK (symptom cannot be duplicated), go
to malfunction simulation tests inAT 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 toAT C - 3 5 , "
How to Perform Trou-
ble Diagnosis for Quick and Accurate Repair",AT C - 3 5 , "SYMPTOM TABLE"and perform applicable trouble
diagnosis procedures.
MJIB0341E
MJIB0342E
MJIB0336E
Page 394 of 3171
ATC-60
TROUBLE DIAGNOSIS
Power Supply and Ground Circuit for Front Air Control
EJS006BJ
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
*1ATC-60, "Power Supply and Ground
CircuitforFrontAirControl".*2ATC-57, "
Operational Check".
MJIB0343E
Page 395 of 3171

TROUBLE DIAGNOSIS
ATC-61
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AT C
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 18°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.
MJIB0327E
MJIB0344E
MJIB0180E
Page 396 of 3171

ATC-62
TROUBLE DIAGNOSIS
1.CHECK POWER SUPPLY CIRCUITS FOR FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect front air control connector.
3. Turn ignition switch ON.
4. Check voltage between front air control harness connector M60
terminals 6 and 19, 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 toPG-83
.
lIf fuses are OK, check harness for open circuit. Repair or replace as necessary.
lIf 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
M60 terminal 20 and ground.
OK or NG
OK >> Replace front air control. Refer toAT C - 11 6 , "REMOVAL"
.
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON Front air
control
connectorTerminal No.
M60 6
GroundApprox. 0V Approx. 0VBattery
voltage
M60 19Battery
voltageBattery
voltageBattery
voltage
WJIA1082E
20 - Ground : Continuity should exist.
WJIA1239E
Page 397 of 3171
TROUBLE DIAGNOSIS
ATC-63
C
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MA
B
AT C
Mode Door Motor CircuitEJS006BK
SYMPTOM:
lAir outlet does not change.
lMode door motor does not operate normally.
INSPECTION FLOW
*1AT C - 3 0 , "Discharge Air Flow".*2AT C - 5 7 , "Operational Check".*3ATC-55, "A/C System Self-diagnosis
Function".
*4AT C - 5 6 , "
SELF-DIAGNOSIS CODE
CHART".*5AT C - 6 5 , "
DIAGNOSTIC PROCE-
DURE FOR MODE DOOR
MOTOR".
MJIB0345E
Page 398 of 3171

ATC-64
TROUBLE DIAGNOSIS
SYSTEM DESCRIPTION
Component Parts
Mode door control system components are:
lFront air control
lMode door motor
lPBR (built into mode door motor)
lIn-vehicle sensor
lAmbient sensor
lOptical sensor
lIntake sensor
System Operation
The mode door position (vent, B/L, foot, and defrost) is set by the front air control by means of the mode door
motor. When a mode door position is selected on the front air control, voltage is applied to one circuit of the
mode door motor while ground is applied to the other circuit, causing the mode door motor to rotate. The direc-
tion of rotation is determined by which circuit has voltage applied to it, and which one has ground applied to it.
The front air control monitors the mode door position by measuring the voltage signal on the PBR circuit.
In AUTO mode the mode door position is set by the front air control which determines the proper position
based on inputs from the in-vehicle sensor, ambient sensor, optical sensor, intake sensor, and the temperature
selected by the driver or passenger.
Mode Door Control Specification
WJIA1240E
WJIA0434E
Page 399 of 3171

TROUBLE DIAGNOSIS
ATC-65
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AT C
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
themodedoor.
NOTE:
This illustration is for LHD models. The layout for RHD models is
symmetrically opposite.
DIAGNOSTIC PROCEDURE FOR MODE DOOR MOTOR
1.CHECK RESULT FROM FRONT AIR CONTROL SELF-DIAGNOSIS
Self-diagnosis code 92 is present. Refer toAT C - 5 5 , "
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 and mode door motor
connector.
3. Check continuity between front air control harness connector
M60 terminal 1 and mode door motor harness connector M46
terminal 1 and between front air control harness connector M60
terminal 14 and mode door motor harness connector M46 termi-
nal 6.
OK or NG
OK >> Replace mode door motor.
NG >> Repair or replace harness as necessary.
MJIB0161E
1 - 1 : Continuity should exist.
14 - 6 : Continuity should exist.
MJIB0204E
Page 400 of 3171
ATC-66
TROUBLE DIAGNOSIS
3.CHECK PBR REFERENCE SIGNAL VOLTAGE
1. Turn ignition switch OFF.
2. Disconnect the mode door motor connector.
3. Turn ignition switch ON.
4. Check voltage between mode door motor harness connector
M46 terminal 3 and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.CHECK PBR REFERENCE VOLTAGE CIRCUIT BETWEEN MODE DOOR AND FRONT AIR CONTROL
1. Turn ignition switch OFF.
2. Disconnect the front air control connector.
3. Check continuity between mode door motor harness connector
M46 terminal 3 and front air control harness connector M60 ter-
minal 23.
OK or NG
OK >> Replace front air control. Refer toAT C - 11 6 , "REMOVAL"
.
NG >> Repair or replace harness as necessary.3 - Ground : Approx. 5V
MJIB0205E
3 - 23 : Continuity should exist.
MJIB0206E