StopOrDrive

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.

P0457 EVAP leak detected (fuel cap loose or off)

Can I drive with P0457?

Drive

Safe to keep driving normally. Fix it when convenient.

It only affects fuel-vapor emissions, not how the engine runs.

What does P0457 mean?

The fuel vapor system found a leak, and the computer believes the gas cap is loose, missing, or not sealing.

What causes P0457?

  1. Gas cap not tightened until it clicks
  2. Worn or cracked gas cap seal
  3. Wrong or poor-fitting replacement cap
  4. Damaged fuel filler neck

How much does it cost to fix P0457?

$0 – $500

Tighten the cap until it clicks; the light usually clears on its own after several days of driving. New cap: $15–$60. Filler neck repair: $200–$500.

Confirm the code yourself

A low-cost scanner lets you read the code, clear it, and see if it comes back before paying for a diagnosis.

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