Page 433 of 3502

TROUBLE DIAGNOSIS
ATC-55
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B
AT C
CHECKING TEMPERATURE INCREASE
1. Press temperature control switch (UP, driver side) until 32°C is displayed.
2. Check for hot air at discharge air outlets.
If NG, go to trouble diagnosis procedure for AT C - 9 1 , "
Insufficient Heating" .
If OK, continue the check.
CHECKING A/C SWITCH
1. Press AUTO switch and 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 AT C - 7 8 , "
Magnet Clutch Circuit" .
If OK, continue the check.
CHECKING AUTO MODE
1. Press AUTO switch and A/C switch.
2. Display should indicate AUTO.
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 AT C - 5 6 , "
Power Supply and Ground Circuit for Auto Amp." , then
if necessary, trouble diagnosis procedure for AT C - 7 8 , "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go to Incident Simulation Tests in GI-24,
"How to Perform Efficient Diagnosis for an Electrical Incident" and perform tests as outlined to simulate driv-
ing conditions environment. If symptom appears, refer to AT C - 3 5 , "
SYMPTOM TABLE" and perform applica-
ble trouble diagnosis procedures.
Page 434 of 3502
ATC-56
TROUBLE DIAGNOSIS
Power Supply and Ground Circuit for Auto Amp.BJS000FZ
SYMPTOM: A/C system does not come on.
INSPECTION FLOW
*1ATC-57, "DIAGNOSIS PROCE-
DURE FOR A/C SYSTEM"
*2ATC-54, "Operational Check"*3AV-58, "Unable to Operate System
with A/C and AV Switch" (Integrated
display system)
*4AV-97, "
Unable to Operate System
with A/C and AV Switch" (Integrated
color display system)
PJIA0004E
Page 435 of 3502

TROUBLE DIAGNOSIS
ATC-57
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AT C
COMPONENT DESCRIPTION
Unified Meter and A/C amp. (Automatic Amplifier)
The unified meter and A/C amp. has a built-in microcomputer which
processes information sent from various sensors needed for air con-
ditioner operation. The air mix door motor, mode door motor, intake
door motor, blower motor and compressor are then controlled.
When the various switches and temperature contorol switch are
operated, data is input to the unified meter and A/C amp. from the
display unit / display control unit using CAN communication.
Self-diagnosis functions are also built into unified meter and A/C
amp. to provide quick check of malfunctions in the auto air condi-
tioner system.
Potentio Temperature Control (PTC)
The PTC is built into the A/C and AV switch. It can be set at an inter-
val of 0.5°C in the 18°C to 32°C temperature range by turning tem-
perature control switch. The set temperature is displayed.
DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
RJIA2732E
RJIA3253E
SJIA0301E
Page 436 of 3502

ATC-58
TROUBLE DIAGNOSIS
1. CHECK POWER SUPPLY CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Disconnect unified meter and A/C amp. connector.
2. Check voltage between unified meter and A/C amp. harness
connector M42 terminals 21, 22 and 35, unified meter and A/C
amp. harness connector M45 terminal 46 and ground.
OK or NG
OK >> GO TO 2.
NG >> Check 10A and 15A fuses [Nos. 6, 10, 11, 12 and 19, located in the fuse block (J/B)]. Refer to PG-
79, "FUSE BLOCK - JUNCTION BOX (J/B)" .
If fuses are OK, check harness for open circuit. Repair or replace if necessary.
If fuses are NG, harness for short circuit and replace fuse.
2. CHECK GROUND CIRCUIT FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch OFF.
2. Check continuity between unified meter and A/C amp. harness
connector M42 terminal 29, 30 and ground.
OK or NG
OK >> Replace unified meter and A/C amp.
NG >> Repair harness or connector.
Terminals Ignition switch position
(+)
(-) OFF ACC ON Unified
meter and
A/C amp.
connectorTerminal No.
M42 21
GroundBattery volt-
ageBattery volt-
ageBattery
voltage
M42 22 Approx. 0 V Approx. 0 VBattery
voltage
M42 35 Approx. 0 VBattery volt-
ageBattery
voltage
M45 46 Approx. 0 V Approx. 0 VBattery
voltage
RJIA1984E
29, 30 – Ground : Continuity should exist.
RJIA1985E
Page 437 of 3502
TROUBLE DIAGNOSIS
ATC-59
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B
AT C
LAN System CircuitBJS000G0
SYMPTOM: Mode door motor, intake door motor and/or air mix door motor(s) does not operate normally.
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT
1. CHECK POWER SUPPLY FOR UNIFIED METER AND A/C AMP.
1. Turn ignition switch ON.
2. Check voltage between unified meter and A/C amp. harness
connector M45 terminal 54 and ground.
OK or NG
OK >> GO TO 2.
NG >> Replace unified meter and A/C amp.
2. CHECK SIGNAL FOR UNIFIED METER AND A/C AMP.
Confirm A/C LAN signal between unified meter and A/C amp. har-
ness connector M45 terminal 43 and ground using an oscilloscope.
OK or NG
OK >> GO TO 3.
NG >> Replace unified meter and A/C amp.
RJIA1775E
54 – Ground : Battery voltage
RJIA1986E
Terminals
Voltag e (+)
(-) Unified meter
and A/C amp.
connectorTe r m i n a l N o .
M45 43 Ground
RJIA1987E
SJIA1453J
Page 438 of 3502
ATC-60
TROUBLE DIAGNOSIS
3. CHECK POWER SUPPLY FOR EACH DOOR MOTOR
Check voltage between each door motor harness connector M252,
M253, M254 and M255 terminal 1 and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK SIGNAL FOR EACH DOOR MOTOR
Confirm A/C LAN signal between each door motor harness connec-
tor terminal 3 and ground using an oscilloscope.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.
5. CHECK MOTOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect each door motor connector.
3. Check continuity between each door motor harness connector
M252, M253, M254 and M255 terminal 2 and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.1 – Ground : Battery voltage
RJIA1988E
Door
motorTe r m i n a l s
Voltage (+)
(-)
Con-
nectorTerminal
No.
Mode M252 3
Ground Air mix
(Driver
side)M253 3
Air mix
(Passen-
ger side)M254 3
Intake M255 3
RJIA1989E
SJIA1453J
2 – Ground : Continuity should exist.
RJIA1990E
Page 439 of 3502

TROUBLE DIAGNOSIS
ATC-61
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AT C
6. CHECK MOTOR OPERATION
1. Reconnect each door motor connector.
2. Turn ignition switch ON.
3. Confirm operation of each door motor.
OK or NG
OK >> (Return to operate normally.)
Poor contact in motor connector.
NG >> (Does not operate normally.)
GO TO 7.
7. CHECK AIR MIX DOOR MOTOR AND INTAKE DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect mode, air mix (driver side, passenger side), and intake door motor connectors.
3. Reconnect air mix (driver side, passenger side) and intake door motor connectors.
4. Turn ignition switch ON.
5. Confirm operation of air mix door motor (driver side, passenger side) and intake door motor.
OK or NG
OK >> [Air mix (driver side, passenger side) and intake door motors operate normally.]
Replace mode door motor.
NG >> [Air mix (driver side, passenger side) and intake door motors does not operate normally.]
GO TO 8.
8. CHECK MODE DOOR MOTOR AND INTAKE DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (driver side, passenger side) connectors.
3. Reconnect mode door motor connector.
4. Turn ignition switch ON.
5. Confirm operation of mode door motor and intake door motor.
OK or NG
OK >> (Mode and intake door motors operate normally.)
GO TO 10.
NG >> (Mode and intake door motors does not operate normally.)
GO TO 9.
9. CHECK MODE DOOR MOTOR AND AIR MIX DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect intake door motor connector.
3. Reconnect air mix door motor (driver side, passenger side) connectors.
4. Turn ignition switch ON.
5. Confirm operation of mode door motor and air mix door motor (driver side, passenger side).
OK or NG
OK >> [Mode and air mix door motor (driver side, passenger side) operate normally.]
Replace intake door motor.
NG >> [Mode and air mix door motor (driver side, passenger side) does not operate normally.]
Replace unified meter and A/C amp.
Page 440 of 3502
ATC-62
TROUBLE DIAGNOSIS
10. CHECK AIR MIX DOOR MOTOR OPERATION
1. Turn ignition switch OFF.
2. Disconnect air mix door motor (driver side) connector.
3. Turn ignition switch ON.
4. Confirm operation of air mix door motor (passenger side).
OK or NG
OK >> [Air mix door motor (passenger side) operates normally.]
Replace air mix door motor (driver side).
NG >> [Air mix door motor (passenger side) does not operate normally.]
Replace air mix door motor (passenger side).