Code No.B1021, B1022: Air thermo sensor system

COMMENTS ON TROUBLE SYMPTOM
This code is set when the air thermo sensor circuit is open (Code No.B1022) or is short (Code No.B1021).

PROBABLE CAUSE

  • Malfunction of the air thermo sensor
  • Damaged wiring harness or connectors
  • Malfunction of the semi automatic air conditioner control panel (A/C-ECU)

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list
Check that the following service data display contents are normal (Refer to ).

  • Item 20: Air thermo sensor

Q. Is the check result normal?
Go to Step 5.
Go to Step 2.

STEP 2. Connector check: B-113 A/C-ECU connector and B-08 air thermo sensor connector




Q. Is the check result normal?

Go to Step 3.

Repair the connector.

STEP 3. Check the wiring harness between B-113 A/C-ECU connector (terminals 12 and 14) and B-08 air thermo sensor connector (terminals 2 and 1).





  • Check the sensor signal line and earth line for open and short circuit.

Q. Is the check result normal?

Go to Step 4.

Repair the wiring harness.

STEP 4. Check the air thermo sensor.
Refer to .

Q. Is the check result normal?
Go to Step 5.
Replace the air thermo sensor.

STEP 5. Check whether the diagnosis code is reset.

Q. Is the diagnosis code set?
Replace the semi automatic air conditioner control panel (A/C-ECU)
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).