DTC B14E7: Heater Core Sensor Circuit Open

DTC detecting condition: 

Heater core sensor circuit is open.

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 B14E7 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. Short the heater core sensor connector (i293).
   4. Turn the ignition switch to ON.
   5. 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:  Replace the heater core sensor. Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>HEATER CORE SENSOR>REMOVAL .

      No:  Go to  3.

3. CHECK HARNESS  .
   1. Turn the ignition switch to OFF.
   2. Restore the temporary shorted lines made in step 2.
   3. Turn the ignition switch to ON.
   4. 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:  Go to  4.

      No:  Repair or replace the open circuit of harness.

4. CHECK HARNESS (OPEN CIRCUIT)  .
   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 - (i88) No. 37:

      (i293) No. 2 - (i88) No. 30:

      Is there continuity?

      Yes:  Replace the A/C control panel. Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>CONTROL PANEL>REMOVAL .

      No:  Repair or replace the open circuit of harness.