P0457 — EVAP Leak Detected (Fuel Cap Loose/Off)

P0457 specifically points to a loose, missing or failed fuel cap. Tighten it until it clicks and drive a few days — the code often clears itself.

Cost range: $0–$150. Severity: low. Safe to drive? Yes. This is the least serious code the car can throw.

Most common causes of P0457

1. Fuel cap not tightened — Tighten until it clicks at least three times. ($0)
2. Cracked or hardened cap seal — Replace the cap — the cheapest possible repair. ($15–$40)
3. Damaged filler neck sealing surface — Rust or a dent prevents a seal. ($150–$500)

Symptoms drivers report with P0457

• Check engine light shortly after refueling
• No performance change