DTC B1446: Air Mix Door Actuator Circuit Stuck (Driver)

WARNING: This page is about a different variant/trim than selected.

DTC detecting condition:

Air mix door actuator is locked.
The potentiometer value of the actuator does not change.

Trouble symptom:

Temperature cannot be adjusted for model without left/right independent air conditioner.
Temperature of the driver's side cannot be adjusted for model with left/right independent air conditioner.

Wiring diagram:

Air conditioning system Ref. to WIRING SYSTEM (IMPREZA MODEL)>AIR CONDITIONING SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>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) (EXCEPT FOR HEV)>GENERAL DESCRIPTION>CAUTION .

CHECK CONNECTOR .
1. Check connecting condition of the A/C control panel connector and air mix door actuator LH connector (with left/right independent air conditioner) or air mix door actuator connector (without left/right independent air conditioner).
2. Turn the ignition switch to ON.
3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS) (EXCEPT FOR HEV)>DIAGNOSTIC TROUBLE CODE (DTC) .
  Is DTC B1446 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.
CHECK ACTUATOR .
Using the Subaru Select Monitor, check the following items in the [Active Test] of [Air Conditioner]. Ref. to AIR CONDITIONER (DIAGNOSTICS) (EXCEPT FOR HEV)> ACTIVE TEST .
- Air mix door actuator target open (driver's side) Does the air mix door actuator LH (with left/right independent air conditioning function) or air mix door actuator (without left/right independent air conditioning function) move to the set target opening angle?
Yes: The circuit of the air mix door actuator LH (with left/right independent air conditioning function) or air mix door actuator (without left/right independent air conditioning function) is normal.

No: Go to 3.
CHECK HARNESS .
Using a tester, measure the voltage between terminals in the air mix door actuator LH connector (with left/right independent air conditioning function) or air mix door actuator connector (without left/right independent air conditioning function).

Connector and terminal

With left/right independent air conditioning function

(1174) No. 3 (+) - (i174) No. 1 (-):

Without left/right independent air conditioning function

(1175) No. 1 (+) - (i175) No. 3 (-):

Is the voltage 4.5 - 5.5 V?

Yes: Go to 4.

No: Repair or replace the open, short circuit of the harness.
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 LH (with left/right independent air conditioning function) or air mix door actuator connector (without left/right independent air conditioning function) terminals.
  Connector and terminal
  
  With left/right independent air conditioning function
  
  (i174) No. 3 - (i88) No. 16:
  
  (i174) No. 1 - (i88) No. 30:
  
  (i174) No. 2 - (i88) No. 35:
  
  (i174) No. 5 - (i88) No. 4:
  
  (1174) No. 4 - (i88) No. 3:
  
  Without left/right independent air conditioning function
  
  (1175) No. 1 - (i88) No. 16:
  
  (i175) No. 3 - (i88) No. 30:
  
  (i175) No. 2 - (i88) No. 35:
  
  (i175) No. 4 - (i88) No. 4:
  
  (i175) No. 5 - (i88) No. 3:
  
  Is there continuity?
  
  Yes: Go to 5.
  
  No: Repair or replace the open circuit of harness.
CHECK AIR MIX DOOR ACTUATOR LH .
Check the parts of the air mix door actuator LH (with left/right independent air conditioning function) or air mix door actuator (without left/right independent air conditioning function).

Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>AIR MIX DOOR ACTUATOR .

Is the air mix door actuator LH (with left/right independent air conditioning function) or air mix door actuator (without left/right independent air conditioning function) normal?

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

No: Replace the air mix door actuator LH (with left/right independent air conditioning function) or air mix door actuator (without left/right independent air conditioning function). Ref. to AIR CONDITIONER (EXCEPT FOR HEV)>AIR MIX DOOR ACTUATOR .