Diagnostic Procedure With Cancel Code: 12

Detected when the brake pedal is depressed, or the error related to the stop light & brake switch occurred.

Trouble symptom: 

• Cruise control cannot be set.
• Cruise control cannot be released.

Wiring diagram: 

Cruise control system Refer to WIRING SYSTEM>CRUISE CONTROL SYSTEM>WIRING DIAGRAM .

• Engine type: FA

  Courtesy of SUBARU OF AMERICA, INC.

  Courtesy of SUBARU OF AMERICA, INC.

1. CHECK STOP LIGHT & BRAKE SWITCH. 

   Check the stop light & brake switch. Refer to CRUISE CONTROL SYSTEM>STOP LIGHT & BRAKE SWITCH .

   Are the check results for the stop light & brake switch unit, and installation position OK?

   Yes:  Go to  2.

   No:  Replace the stop light & brake switch. Or adjust the installation position.

2. CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the stop light & brake switch harness connector.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between harness connector terminal and chassis ground.

      Connector & terminal 

      (B65) No. 1 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  3.

   No: 

   • Check the fuse No. 8 (fuse & relay box).
   • Check for open or short circuit in harness between the stop light & brake switch and the fuse & relay box.
3. CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. 

   Measure the voltage between harness connector terminal and chassis ground.

   Connector & terminal 

   (B65) No. 3 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  4.

   No: 

   • Check the fuse No. 4 (fuse & relay box).
   • Check for open or short circuit in harness between the stop light & brake switch and the fuse & relay box.
4. CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the harness connector of ECM.
   3. Measure the resistance between ECM harness connector terminal and stop light & brake switch harness connector terminal.

      Connector & terminal 

      Engine type: FA 

      (B134) No. 43 - (B65) No. 4:

      (E158) No. 8 - (B65) No. 2:

      Engine type: EJ 

      (B136) No. 3 - (B65) No. 2:

      (B136) No. 15 - (B65) No. 4:

   Is the resistance less than 10 Ω?

   Yes:  Replace the ECM.

   Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>ENGINE CONTROL MODULE (ECM) . Refer to FUEL INJECTION (FUEL SYSTEMS) (STI)>ENGINE CONTROL MODULE (ECM) .

   No:  Repair the harness.