Service Engine Soon/Check Engine Warning Light
The SERVICE ENGINE SOON warning light indicates a malfunction in the engine control system. If functioning correctly, the light comes on when ignition is turned on and goes out when engine is started.
If light fails to come on with ignition on or remains on when engine is running, a service need is indicated. A 2 or 3-digit trouble code will be stored into memory if a problem is detected. When problems causing trouble codes are repaired the, light should return to normal function.