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 CAUSES

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

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-44 A/C-ECU connector and C-45 air thermo sensor connector

Q. Is the check result normal?

Go to Step 2.

Repair the connector.

STEP 2. Check the wiring harness between C-44 A/C-ECU connector (terminals 39 and 38) and C-45 air thermo sensor connector (terminals 2 and 1).

note

Prior to the wiring harness inspection, check joint connector C-138, and repair if necessary.

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

Q. Is the check result normal?

Go to Step 3.

Repair the wiring harness.

STEP 3. Replace the A/C evaporator air outlet thermistor, and then recheck the trouble symptom.

Check that the A/C works normally.

Q. Is the check result normal?

	This diagnosis is complete.

	Go to Step 4.

STEP 4. M.U.T.-III diagnosis code

Q. Is the diagnosis code set?

	Replace the automatic A/C control panel (A/C-ECU).

	The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).