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.

CAUTION:

Before performing diagnosis, refer to "CAUTION" in "General Description". Ref. to AIR CONDITIONER (DIAGNOSTICS)>GENERAL DESCRIPTION>CAUTION

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.
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.
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.
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.