DTC B1440: Air Mix Door Actuator Circuit Open (Driver)

DTC detecting condition: 

Air mix door actuator potentiometer circuit is open.

Trouble symptom: 

Temperature cannot be adjusted.

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 air mix 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 B1440 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 air mix door actuator.
   3. Short No. 2 and No. 3 of i174 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 B1442 displayed? (Current malfunction)

   Yes  : Replace the air mix door actuator. Ref. to AIR CONDITIONER (HEV)>AIR MIX 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. Using a tester, measure the voltage between air mix door actuator connector terminals.

      Connector & terminal 

      (i174) No. 1 (+) - (i174) No. 3 (-):

   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 the continuity between A/C control panel connector and air mix door actuator connector terminals.

      Connector & terminal 

      (i174) No. 1 - (i181) No. 7:

      (i174) No. 3 - (i181) No. 19:

      (i174) No. 2 - (i80) No. 2:

   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.