My car's check engine light is on, what do I do?

When you start your vehicle, the check engine light should come on momentarily to test the engine/emission control system and bulb. If it stays on, it's there to tell the vehicle owner that the car's computer system (OBD-II) has detected a fault. When the CEL is triggered, a fault code or trouble code is stored in the car's computer.

Once the CEL is lit up, you need to get the OBD-II trouble codes read. There are a few options for this:

Once the code is read, you can look it up on the Check Engine Light home page here. That will provide some assistance in knowing where to look. Another good resource once you have the trouble code is

Tip: The check engine light indicates a problem. Sometimes it's more serious than others so don't delay in getting the codes read! In some states the illumination of the CEL means you won't pass your next emmissions test, so keep that in mind.

See also: How do I reset or turn off my check engine light?