What this site does
When your car stores a trouble code, a scanner shows you something like P0420 and a line of technical jargon. We explain what the code means for you as a driver: whether it's safe to keep driving, what usually causes it, how a mechanic tracks it down and roughly what the repair costs.
Where the information comes from
- Code definitions and technical details come from OBDex, an open database of generic OBD-II codes released into the public domain (CC0). It follows the SAE J2012 standard and lists its sources for each code, from regulations and manufacturer documents to public references.
- "Vehicles that report this code" is based on the public complaints database of the US National Highway Traffic Safety Administration (NHTSA). We count owner complaints that mention the code. These are unverified reports from drivers about vehicles sold in the US, and the numbers are complaint counts, not failure rates: models with more cars on the road get more complaints.
- Plain-language explanations, the answers to "Can I drive?" and the diagnosis steps are written by us from these sources and general repair knowledge. They have not all been checked by a professional technician yet: each page says whether it has.
- Repair costs are rough ranges for parts and labor. They are currently based on European estimates converted to US dollars, and real prices vary a lot by vehicle, region and shop. Always get a quote before you approve a repair.
Please read this before you work on your car
Everything here is general information, not a diagnosis of your specific vehicle. If the check engine light is flashing, the brakes or steering feel different, or the airbag light is on, have the car checked before you drive it further. Airbag systems can deploy and injure you: leave them to a shop.
Independence
EngineLightCodes is an independent site. We are not affiliated with NHTSA, SAE International or any vehicle manufacturer.
Contact and corrections
Found a mistake or have a suggestion? Email contact@enginelightcodes.com. We read every message and fix errors as soon as we can confirm them. We can't diagnose individual cars by email.