DTC B1438: Mode Door Actuator Circuit Open

DTC detecting condition: 

Mode door actuator potentiometer circuit is open.

Trouble symptom: 

Vent does not change.

Wiring diagram: 

Air conditioning system Ref. to WIRING SYSTEM (CROSSTREK MODEL (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 mode door actuator 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) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B1438 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 ACTUATOR  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the mode door actuator.
   3. Short No. 1 and No. 2 in (i176) 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) (HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B1439 displayed? (Current malfunction)

   Yes  : Replace the mode door actuator. Ref. to AIR CONDITIONER (HEV)>MODE DOOR ACTUATOR .

   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. Measure the voltage between mode door actuator connector terminals using a tester.

      Connector & terminal 

      (i176) No. 3 (+) - (i176) No. 1 (-):

   Is the voltage 4.5 - 5.5 V?

   Yes  : Go to  4.

   No  : Repair 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 A/C control panel connector and mode door actuator connector terminals.

      Connector & terminal 

      (i176) No. 1 - (i181) No. 19:

      (i176) No. 2 - (i80) No. 11:

      (i176) No. 3 - (i181) No. 7

   Is there continuity?

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

   No  : Repair or replace the open circuit of harness.