There’s a huge percentage of vehicle on the road, right now, with the check engine light illuminated. Many of them have had it on for years, even. Frequently, a check engine light will illuminate, but pose no immediate problems, so people just get used to it and learn to live with it being on. However, Harold's Used Auto Parts Inc in Philadelphia, PA would like you to know that it’s worth having it looked into. Typically, the problem can be diagnosed by simply plugging your car into our computer; the vehicle gives us a code, and we know what the problem is immediately.