Diagnostic Procedure with Cancel Code: 12: Wiring Diagram

Fig 1: Stop Light And Brake Switch Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

Step	Check	Yes	No
1 CHECK STOP LIGHT & BRAKE SWITCH. Check the stop light & brake switch. Refer to STOP LIGHT & BRAKE SWITCH .	Is the stop light & brake switch and installation position OK?	Go to step 2.	Replace the stop light & brake switch. Or adjust the installation position.
2 CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. Turn the ignition switch to OFF. Disconnect the stop light & brake switch harness connector. Turn the ignition switch to ON. Measure the voltage between harness connector terminal and chassis ground. Connector & terminal (B65) No. 2 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 3.	Check fuse No. 8 (in fuse & relay box). Check for open or short circuit in the harness between stop light/brake switch and fuse and relay box.
3 CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. Measure the voltage between harness connector terminal and chassis ground. Connector & terminal (B65) No. 4 (+) - Chassis ground (-):	Is the voltage 10 V or more?	Go to step 4.	Check fuse No. 4 (in fuse & relay box). Check for open or short circuit in the harness between stop light/brake switch and fuse and relay box.
4 CHECK STOP LIGHT & BRAKE SWITCH CIRCUIT. Turn the ignition switch to OFF. Disconnect the harness connector of ECM. Measure the resistance between ECM harness connector terminal and stop light & brake switch harness connector terminal. Connector & terminal (B136) No. 3 - (B65) No. 3: (B136) No. 15 - (B65) No. 1:	Is the resistance less than 10 Ω?	Replace the ECM. Refer to ENGINE CONTROL MODULE (ECM) . Refer to ENGINE CONTROL MODULE (ECM) . Refer to ENGINE CONTROL MODULE (ECM) .	Repair the harness.