DTC B14E1: Air Mix Door Actuator Stepping Motor Circuit Open (Driver)

DTC detecting condition: 

Open circuit in the air mix door actuator stepping motor circuit is detected for 3 seconds or more.

Trouble symptom: 

Temperature cannot be adjusted.

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR. 
   1. Check the condition of connector connection.
   2. Read the DTC using Subaru Select Monitor. Refer to HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)>READ DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC B14E1 displayed?

   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 connector.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between the air mix door actuator connector terminal and chassis ground.

   Connector & terminal 

   Without left/right independent air conditioning function 

   (B239) No. 3 (+) - Chassis ground (-):

   With left/right independent air conditioning function 

   (B235) No. 3 (+) - Chassis ground (-):

   Is the voltage approx. 10 V or more?

   Yes:  Go to  3.

   No  Check the DC power supply circuit.

3. CHECK AIR MIX DOOR ACTUATOR. 
   1. Turn the ignition switch to OFF.
   2. Measure the internal resistance of the air mix door actuator using a tester.

   Terminals 

   Without left/right independent air conditioning function 

   Air mix door actuator

   No. 3 - No. 1:

   No. 3 - No. 2:

   No. 3 - No. 5:

   No. 3 - No. 6:

   With left/right independent air conditioning function 

   Air mix door actuator LH

   No. 3 - No. 1:

   No. 3 - No. 2:

   No. 3 - No. 5:

   No. 3 - No. 6:

   Is the resistance 80 - 100 Ω?

   Yes:  Go to  4.

   No  Replace the actuator. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>AIR MIX DOOR ACTUATOR>REMOVAL .

4. CHECK HARNESS BETWEEN A/C CONTROL PANEL AND AIR MIX DOOR ACTUATOR (OPEN). 
   1. Disconnect the A/C control panel connector.
   2. Measure the resistance between A/C control panel and air mix door actuator connector.

   Connector & terminal 

   Without left/right independent air conditioning function 

   (B239) No. 1 - (i88) No. 28:

   (B239) No. 2 - (i88) No. 27:

   (B239) No. 5 - (i88) No. 26:

   (B239) No. 6 - (i88) No. 25:

   With left/right independent air conditioning function 

   (B235) No. 1 - (i88) No. 24:

   (B235) No. 2 - (i88) No. 23:

   (B235) No. 5 - (i88) No. 22:

   (B235) No. 6 - (i88) No. 21:

   Is there continuity?

   Yes  Replace the A/C control panel. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>CONTROL PANEL>REMOVAL .

   No  Repair or replace the open circuit of harness.