The light could be a minor issue, such as a faulty gas cap, or it could mean something more serious, such as a misfiring engine. ... If the light begins flashing, however, it indicates a more serious problem, such as a misfire that can quickly overheat the catalytic converter.

What is the most common reason for check engine light?

Replacing a faulty oxygen sensor — a sensor used to optimize a vehicle's fuel-to-air mixture to increase gas mileage and reduce emissions — is the most common cause for a check engine light.

Is it safe to drive your car with the check engine light on?

If the check engine light comes on while you're driving, it can be unnerving. Don't panic, though. ... The check engine light means there's a problem somewhere in your emissions system. Regardless, you're safe to drive for now as long as the car isn't performing strangely.