DTC B14E8: Heater Core Sensor Circuit Short-Circuit

DTC detecting condition: 

Heater core sensor circuit is shorted.

Trouble symptom: 

Proper outlet air temperature cannot be kept during Auto Start Stop.

Wiring diagram: 

Air conditioning system Ref. to WIRING SYSTEM (IMPREZA MODEL)>AIR CONDITIONING SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .
   1. Check connecting condition of the A/C control panel connector and heater core sensor connector.
   2. Turn the ignition switch to ON.
   3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .

      Is DTC B14E8 displayed? (Current malfunction)

      Yes:  Go to  2.

      No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

      NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK HEATER CORE SENSOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the heater core sensor.
   3. Turn the ignition switch to ON.
   4. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .

      Is DTC B14E7 displayed? (Current malfunction)

      Yes:  Replace the heater core sensor. Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>HEATER CORE SENSOR>REMOVAL .

      No:  Go to  3.

3. CHECK HARNESS  .

   Using the tester, measure the voltage between terminals.

   Connector and terminal 

   (i293) No. 2 (+) - (i293) No. 1 (-):

   Is the voltage 4.5 - 5.5 V?

   Yes:  Check the connection of the heater core sensor circuit.

   No:  Go to  4.

4. CHECK HARNESS (SHORTED BETWEEN LINES)  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the A/C control panel.
   3. Using a tester, check continuity between terminals.

      Connector and terminal 

      (i293) No. 1 - (i293) No. 2:

      Is there continuity?

      Yes:  Repair or replace the short circuit of the harness.

      No:  Replace the A/C control panel. Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>CONTROL PANEL>REMOVAL .