Code No.B1031: Fin thermo Sensor system (short circuit) <Vehicles without A/C>
Code No.B1032: Fin thermo Sensor system (open circuit) <Vehicles without A/C>








COMMENTS ON TROUBLE SYMPTOM
This code is set when the fin thermo sensor circuit is short (Code No.B1031) or is open (Code No.B1032).

PROBABLE CAUSES

  • Malfunction of the fin thermo sensor
  • Damaged the wiring harness or connectors
  • Malfunction of the heater control unit

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-59 heater control unit connector and C-118 fin thermo sensor connector

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

STEP 2. Check the wiring harness between C-59 heater control unit connector (terminals 21 and 22) and C-118 fin thermo sensor connector (terminals 2 and 1).

  • 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. Check the fin thermo sensor.
Refer to .

Q. Is the check result normal?
Go to Step 4.
Replace the fin thermo sensor.

STEP 4. Check whether the diagnosis code is reset.

Q. Is the diagnosis code set?
Replace the heater control unit.
The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).