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

DTC detecting condition:

Air mix door actuator is locked.

Trouble symptom:

Temperature on the driver's side cannot be adjusted.

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

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CHECK CONNECTOR .
1. Turn the ignition switch to OFF.
2. Check connecting condition of the A/C control panel connector and air mix door actuator LH connector.
Is the check result OK?

Yes: Go to 2.

No: Repair the connector.
CHECK DTC .
1. Turn the ignition switch to ON.
2. Set the ON/OFF button to ON.
3. Set the temperature control to MAX COOL. (Driver's side, passenger's side)
4. Leave it for 16 seconds or more.
5. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1446 displayed? (Current code)

Yes: Go to 4.

No: Go to 3.
CHECK DTC .
1. Set the temperature control to MAX HOT. (Driver's side, passenger's side)
2. Leave it for 16 seconds or more.
3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
Is DTC B1446 displayed? (Current code)

Yes: Go to 4.

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.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK HARNESS (OPEN CIRCUIT) .
1. Turn the ignition switch to OFF.
2. Disconnect the connectors from the air mix door actuator LH and the A/C control panel.
  Ref. to AIR CONDITIONER>AIR MIX DOOR ACTUATOR>REMOVAL . Ref. to AIR CONDITIONER>CONTROL PANEL>REMOVAL .
3. Using a tester, check the continuity between the A/C control panel connector and air mix door actuator LH terminals.
  Connector & terminal
  
  (B148) No. 3 - (i130) No. 16:
  
  (B148) No. 1 - (i130) No. 30:
  
  (B148) No. 5 - (i130) No. 35:
  
  (B148) No. 7 - (i130) No. 4:
  
  (B148) No. 6 - (i130) No. 3:
Is there continuity?

Yes: Go to 5.

No: Repair or replace the open circuit of harness.
CHECK HARNESS (SHORTED BETWEEN LINES AND SHORTED TO GROUND) .
Using a tester, check the continuity between terminals in air mix door actuator LH connector and between air mix door actuator LH connector and chassis ground.

Connector & terminal

(B148) No. 6 - (B148) No. 7:

(B148) No. 6 - Chassis ground:

(B148) No. 7 - Chassis ground:

Is there continuity?

Yes: Repair or replace the short circuit of the harness.

No: Go to 6.
CHECK AIR MIX DOOR ACTUATOR LH UNIT .
Check the air mix door actuator LH unit. Ref. to AIR CONDITIONER>AIR MIX DOOR ACTUATOR>INSPECTION .

Is the check result OK?

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

No: Replace the air mix door actuator LH. Ref. to AIR CONDITIONER>AIR MIX DOOR ACTUATOR .