Ford Focus 1.4 zetec se
02 plate
35,550 miles

Any suggestions please!

My Focus brokedown in work last week and went on diagnostics and had new coil pack plugs and leads which has now solved the problem after a wallet busting £153

After a few days the engine managment light on the dash has come on and has been on ever since the car is running fine no problems but I dont understand why the light is staying on all the time Ive been told that it sometimes happens and will stay on all the time but why is this?