AB4 Verify ECU Function

- Key ON.

- Pull DTCs with NGS. Reading and Clearing Diagnostic Trouble Codes

- Was code C1225 set?

YES -- Brake lamp detection circuit in ECU is defective and not recognizing proper lamp function. Replace ECU. Go to AB12 to verify concern is resolved. AB12 Verify All Steps Have Been Completed

NO -- ECU is functioning properly. Go to AB6 to diagnose intermittent wiring fault. AB6 Diagnose Intermittent Wiring Concern