StopOrDrive

This free site is for U.S. drivers whose check engine light just came on: type the OBD-II code from your scanner or parts-store readout, and it tells you what the code means, whether you can still drive, the most likely causes, and what the repair typically costs.

Enter a 5-character code such as P0420, P0301, or P0457.

We don't have that code yet

Codes starting with P are engine and transmission, B are body, C are chassis, and U are network communication. A 0 as the second character means a generic code shared by all makes; a 1 means a manufacturer-specific code, so its meaning depends on your brand.

A steady check engine light usually means get it checked soon. A flashing check engine light means an active misfire: reduce speed and stop driving as soon as it is safe.

That doesn't look like an OBD-II code

A valid code is one letter (P, B, C, or U) followed by four characters, for example P0420.

Codes in this decoder:

Misfire: P0300 P0301 P0302 P0303 P0304 P0305 P0306

Fuel/air: P0087 P0101 P0102 P0113 P0171 P0172 P0174 P0175 P0299

Timing/sensors: P0011 P0014 P0016 P0325 P0335 P0340

Cooling: P0117 P0118 P0128 P0217

O2/catalyst: P0133 P0135 P0141 P0420 P0430 P2097

EVAP/emissions: P0401 P0411 P0440 P0442 P0446 P0455 P0456 P0457 P0496

Idle/engine: P0505 P0507 P0521 P0524 P0562 P0606

Transmission: P0700 P0715 P0730 P0741

Network: U0100