My Father in law had a ford mondeo, his engine mangement light came on and stayed on but the car was running fine. The garage said it was just the sensors that occasionly play up and whilst ever it was running fine just to ignore it. He ran it like this for about 3 years and it never missed a beat. The garage said just to disconnect the battery and it would go off, he did this a few times and it did go off but kept coming back on after a week or so. Remember if you do this youll need your radio code.