A steady check engine light usually means something needs attention soon. A flashing check engine light is a different message: it means the engine is misfiring badly right now, and that can damage expensive parts within minutes.
What a flashing light means
A flash almost always signals a serious misfire, where one or more cylinders are not burning fuel properly. Unburned fuel then dumps into the exhaust and can overheat and destroy the catalytic converter, which is costly to replace.
What to do immediately
Ease off the accelerator and reduce your speed. Avoid hard acceleration and heavy loads. If you can, get off the road and let the engine idle gently, then arrange to have it checked before driving far.
Common causes of a misfire
- A failing ignition coil or worn spark plug.
- A clogged or leaking fuel injector.
- A vacuum leak upsetting the air and fuel mix.
Frequently asked questions
Can I drive with a flashing check engine light?
Only gently and only as far as needed to get somewhere safe. Continued hard driving risks the catalytic converter.
Will the light stop flashing on its own?
It may go steady if the misfire settles, but the underlying fault still needs fixing.
A code reader tells you which cylinder is misfiring. See our car accessory guides.
