P0457 Code: EVAP Leak (Loose Fuel Cap) — Causes & Fix
P0457 means the evaporative emissions (EVAP) system detected a leak traced to the fuel cap — usually loose, missing, or a bad seal.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $0 – $100
- Time to fix
- 30 minutes – 2 hours
What it means
The most common cause is a fuel cap that isn't sealing; others are a damaged filler neck or cap seal. P0457 is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer petrol car or light truck regardless of make. Fix the underlying fault, then clear the code with an OBD-II scan tool — it will return if the problem isn't resolved.
Symptoms
- Check engine light on
- No drivability effect
- Possible faint fuel smell
How to fix it
- 1
Re-seat or replace the fuel cap
1. Remove and re-tighten the cap until it clicks. 2. Replace a worn cap or damaged seal.
- 2
Check the filler neck
1. Inspect the filler neck sealing surface. 2. Repair, then clear the code (may need a drive cycle to reset).
Frequently asked questions
Will P0457 clear itself after tightening the cap?
Often yes — after several drive cycles with a properly sealed cap. You can also clear it with a scan tool once the cap is fixed.
Last updated July 19, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.