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. Check connecting condition of the A/C control panel connector and the temperature and humidity 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)>DIAGNOSTIC TROUBLE CODE (DTC) .

      Is DTC B14EC 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 TEMPERATURE AND HUMIDITY SENSOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the temperature and humidity sensor.
   3. Short the connector (i173).
   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 malfunction)

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

      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 a tester, measure the voltage between terminals in temperature and humidity sensor connector.

      Connector and terminal 

      (i173) No. 3 (+) - (i173) No. 2 (-):

   Is the voltage 4.5 - 5.0 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 the continuity between the A/C control panel connector and temperature and humidity sensor connector.

      Connector and terminal 

      (i173) No. 2 - (i88) No. 14:

      (i173) No. 3 - (i88) No. 33:

   Is there continuity?

   Yes  : Replace the A/C control panel. Ref. to AIR CONDITIONER>CONTROL PANEL .

   No  : Repair or replace the open circuit of harness.