A check-engine light could be a gentle reminder or a sign of something catastrophic. We explain what a malfunction indicator light is and what you can do about it.

Three weeks later, after I changed my oil, I noticed that the check engine light was off. Did the light burn out? No, because when I turn the key to start the car, I see it light up.

When your car's oil has just been changed, it should be at its best, right? So why is it that sometimes after an oil change, the check enging light comes on?