DTC B14EC: Humidity Sensor Circuit Open

DTC detecting condition: 

Temperature and humidity sensor circuit is open.

Trouble symptom: 

Proper outlet air temperature cannot be kept.

Wiring diagram: 

Air conditioning system Ref. to WIRING SYSTEM>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check connecting condition of the A/C control module connector and temperature and humidity sensor connector.

   Is the check result OK?

   Yes:  Go to  2.

   No:  Repair the connector.

2. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B14EC displayed? (Current code)

   Yes:  Go to  3.

   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.
3. CHECK TEMPERATURE AND HUMIDITY SENSOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from the temperature and humidity sensor. Ref. to AIR CONDITIONER>TEMPERATURE AND HUMIDITY SENSOR .
   3. Short No. 2 and No. 3 in (i154) connector.
   4. Turn the ignition switch to ON.
   5. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B14ED displayed? (Current code)

   Yes:  Replace the temperature and humidity sensor. Ref. to AIR CONDITIONER>TEMPERATURE AND HUMIDITY SENSOR .

   No:  Go to  4.

4. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Turn the ignition switch to OFF.
   2. Restore the temporary shorted lines made in step 3.
   3. Disconnect the connector from A/C control module. Ref. to AIR CONDITIONER>CONTROL UNIT .
   4. Using a tester, check the continuity between the A/C control module connector and temperature and humidity sensor connector.

      Connector & terminal 

      (i154) No. 2 - (i107) No. 14:

      (i154) No. 3 - (i107) No. 33:

      (i154) No. 4 - (i107) No. 10:

   Is there continuity?

   Yes:  Replace the A/C control module. Ref. to AIR CONDITIONER>CONTROL UNIT .

   No:  Repair or replace the open circuit of harness.