What usually causes P0457?

Filler cap not tightened or seal damaged.

P0457EVAP system leak detected (fuel cap loose/off)

P0457 means “EVAP system leak detected (fuel cap loose/off)”. It's a generic powertrain code (auxiliary emission controls), so it means the same on every make, including VW, Škoda, Audi, SEAT and Cupra.

Not urgent
SystemEmissions
TypeGeneric (same on all makes)
VCDS number16841

How urgent is it?

Usually not urgent; often emissions-related.

Which system and module

Scanline files it under Emissions. The first letter, P, means powertrain (engine, transmission, emissions).

Usually stored by the engine control unit (VCDS address 01, Engine).

What usually causes it

Filler cap not tightened or seal damaged

Typical causes are a starting point, not a diagnosis of your car.

Related codes

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Scanline explains fault codes; it isn't a repair authority. This page explains what the code means; it can't tell you what is wrong with your car. Ross-Tech's wiki has their own notes on VW Group faults.