DTC B278D Id Code Box Recognition Judgment Abnormal

DTC DETECTING CONDITION: 

When ID code box setting is set to OFF, ID code box LIN signal is received.

TROUBLE SYMPTOM: 

Engine will not start.

WIRING DIAGRAM: 

Push button start system Ref. to WIRING SYSTEM > Push Button Start System >  WIRING DIAGRAM  .

Fig 1: Push Button Start System Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .
   1. Turn the ignition switch to OFF.
   2. Using the Subaru Select Monitor, clear the keyless access system memory. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS) >  Clear Memory Mode   .
   3. Turn the ignition switch to OFF → ON.
   4. Use the Subaru Select Monitor and read DTCs. Ref. to KEYLESS ACCESS WITH PUSH BUTTON START SYSTEM (DIAGNOSTICS) >  Read Diagnostic Trouble Code (DTC)   .

   Is B278D displayed?

   Yes: Go to   2  .

   No: System is normal. It is possible that temporary poor contact occurs.

2. CHECK HARNESS  .
   1. Disconnect the keyless access CM connector.
   2. Measure the resistance between keyless access CM connector and chassis ground.

      Connector & terminal 

      (B573) No. 15 - Chassis ground:

   No: ID code box: Is the resistance 10 kΩ or more? Or is the terminal (B573) No. 15 disconnected?

   With ID code box: Is the resistance 1 Ω or less?

   Yes: Replace the keyless access CM. Ref. to SECURITY AND LOCKS >  KEYLESS ACCESS CM  .

   No: Repair or replace the short circuit of the harness.