
FULL-AUTOMATIC AIR CONDITIONER –
Troubleshooting
55-37
Code No.21 Air thermo sensor system (open circuit)
Probable cause
This diagnosis code is output if the power supply line or input line of the air thermo
sensor is open-circuited and no air thermo sensor signals are input to A/C-ECU.
D
Malfunction of the air thermo sensor
D
Malfunction of connector, harness
D
Malfunction of the A/C-ECU
Air thermo sensor check (Refer to P.55-22.)
NG
Replace
OK
Measure at the air thermo sensor connector B-03.
D
Disconnect the connector, and measure at the harness
side connector.
D
Voltage between terminal (2) and body earth
OK: 5 V
NG
Check the following connector:
B-04
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the air thermo sensor and the
A/C-ECU.
NG
Repair
OK
Replace the A/C-ECU.
OK
Measure at the A/C-ECU connector B-04.
D
Connect the connector.
D
Voltage between terminal (8) and body earth
OK: 2.3 – 2.9 V
NG
Check the following connector:
B-03
NG
Repair
OK
Check the trouble symptom.
NG
Check the harness between the air thermo sensor and the
A/C-ECU, and repair if necessary.
OK
Check the following connector: B-04
NG
Repair
OK
Check the trouble symptom.
NG
Replace the A/C-ECU.
Code No.22 Air thermo sensor system (short circuit)
Probable cause
This diagnosis code is output if the power supply line or output line of the air thermo
sensor is short-circuited and air thermo sensor power supply voltage signals are
input to A/C-ECU.
D
Malfunction of the air thermo sensor
D
Malfunction of connector, harness
D
Malfunction of the A/C-ECU
Air thermo sensor check (Refer to P.55-22.)
NG
Replace
OK
Measure at the A/C-ECU connector B-04.
D
Connect the connector.
D
Voltage between terminal (8) and body earth
OK: 2.3 – 2.9 V
NG
Check the harness between the air thermo sensor and the
A/C-ECU, and repair if necessary.
OK
Replace the A/C-ECU.