OBD-II codelookup.
Enter any check engine code (like P0420) to get its meaning, severity, common causes and how to fix it. Free, no sign-up — works for any OBD-II code, with detailed info on the most common ones.
Try P0420, P0300, P0171, or P0455.
Common check engine codes
The codes drivers look up most — click for full details:
Embed this OBD code lookup free
Run an auto blog, forum or repair site? Add this free code lookup to your page:
How to read an OBD-II code
| Character | Meaning |
|---|---|
| 1st letter | System: P Powertrain, B Body, C Chassis, U Network |
| 2nd digit | 0 = generic (SAE standard), 1 = manufacturer-specific |
| 3rd digit | Subsystem (fuel/air, ignition, emissions, speed, transmission…) |
| 4th–5th | The specific fault number |
Check engine codes, answered.
What is an OBD-II code?
A 5-character code your car's computer stores when it detects a fault. The first letter is the system (P/B/C/U) and the digits pinpoint the issue.
Is this lookup free?
Yes — completely free, no sign-up. Enter any code for its meaning, severity, causes and fixes.
Can I drive with the check engine light on?
Depends on the code. A steady light for a minor fault is often okay short-term; a flashing light or a misfire/overheating code means stop and get it checked.
How do I clear a code?
Fix the underlying problem, then clear the code with an OBD-II scanner. Clearing it without fixing the cause will just bring the light back.