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P0457 — Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)

informational

What it means

The control module detected a leak immediately after a refuelling event and attributes it to the fuel filler cap: the tank pressure sensor sees no seal once the fuel level has changed. Many vehicles show a separate dashboard message such as check gas cap alongside this code. The code often clears by itself after a few drive cycles once the cap is properly refitted.

Likely causes (most common first)

  1. Fuel cap left off or not tightened until it clicks
  2. Worn, cracked or dirty cap seal
  3. Non-original cap that does not match the system pressure specification
  4. Damaged or deformed filler neck thread and sealing surface
  5. Refuelling with the ignition on, so the test starts with the flap open
  6. Faulty fuel tank pressure sensor or a leak elsewhere wrongly attributed to the cap

Can you drive with it?

Yes, driving is completely safe: tighten the fuel cap and the code usually disappears on its own.

This is the generic meaning. What about your car?

The same code has different typical culprits on different engines. Tell the AI your make, model and year — it will rank the causes for your exact car and give you a check order.

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