Faulty Brake Switch
Brake Switch harness is open or shorted
Brake Switch circuit poor electrical connection
Misadjusted Brake Switch
Engine Light ON (or Service Engine Soon Warning Light)
Stop lights may be inoperative
This brake switch send a signal to the Engine Control Module (ECM). The signal is used to detect when the brakes have been applied. In some models the brake switch signal voltage is the same as the voltage supplied to the stop lights.