Are you referring to the check engine light? If so, and it is flashing, stop driving your car and take it in to a professional right away to have it checked out. If the light is constant, it*s most likely not an emergency, but you should still have it checked out as soon as possible. The check engine light can indicate a number of problems ranging from a loose gas cap to a major engine problem. There is no way of knowing why the light illuminated without having it diagnosed by a professional. If you are having trouble finding a technician you trust, check out Ask Patty*s list of female friendly shops in your area.
〉 Answered on Jan 3rd, 2009 by Suzanne Grego, Technician at City of Philadelphia Fleet Management