What should you do when your car's check engine light comes on?
What is wrong if the check engine light comes on at idle and the engine run rough on a 1994 Mazda 929?
The check engine or service engine soon light comes on to alert you that there is or was a problem with the emissions system on your vehicle. If the light comes on steady and stays on, it means that there is a problem and you should have it checked out soon. If it comes on and flashes, it means you will cause damage if you continue driving.