Check Body Integrated Unit Power Supply And Ground Circuit

Wiring diagram: 

Door lock control system Ref. to WIRING SYSTEM>DOOR LOCK CONTROL SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK FUSE  .
   1. Turn the ignition switch to OFF.
   2. Check the fuse on the upstream of the body integrated unit. Ref. to SECURITY AND LOCKS>RELAY AND FUSE>INSPECTION 

   Is the check result OK?

   Yes  : Go to  2.

   No  : Replace the defective fuse.

2. CHECK POWER SUPPLY  .
   1. Disconnect the connector of body integrated unit.
   2. Measure the voltage between the body integrated unit connector and chassis ground.

      Connector & terminal 

      (B71) No. 1 (+) - Chassis ground (-):

      (B73) No. 7 (+) - Chassis ground (-):

      (B72) No. 4 (+) - Chassis ground (-):

      (B2) No. 3 (+) - Chassis ground (-):

   Is the voltage 9 V or more?

   Yes  : Go to  3.

   No  : Check the harness for open or short circuit between body integrated unit and fuse.

3. CHECK GROUND CIRCUIT  .

   Measure the resistance between the body integrated unit connector and chassis ground.

   Connector & terminal 

   (i81) No. 4 - Chassis ground:

   (B72) No. 1 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes  : The power supply and ground circuit are OK.

   No  : Repair or replace the defective part.