(Gasoline) MIL Command

Display shows ON or OFF. The MIL (Service Engine Soon or Check Engine) is controlled by both the AF ECU and the gasoline control module (VCM/PCM or ECM). This display indicates ON whenever the GASOLINE control module commands the MIL ON. The internal circuitry of the AF ECU monitors, but does not affect, the gasoline control modules operation of the MIL. The MIL is illuminated if either module has detected a problem that affects vehicle emissions, driveability or could cause powertrain damage. The gasoline control module illuminates the MIL when the ignition is ON and the engine OFF in order to perform a bulb test.