P0457

EVAP System Leak Detected (fuel cap loose/off)

Evaporative emissions (EVAP) Generic OBD-II Low

What it means

P0457 means the evaporative emission system detected a leak that it traced to a loose or missing fuel cap — vapors that should stay sealed in the tank and charcoal canister are escaping. Nine times out of ten it's simply a cap that wasn't tightened or has a worn seal. The car drives fine; the concern is emissions and fuel-vapor loss.

Low

Can I keep driving? Yes — the car drives normally; this is an emissions and fuel-vapor issue, not a mechanical one.

Real-world scan data

Seen in

287

scans in the past year

Found in

0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0457 scans

P0456in 60.6% of scans

P0455in 25.8% of scans

P0420in 18.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Occasional smell of fuel vapor near the vehicle
Failed emissions test

Common causes

Most likely first

Loose, missing, or worn fuel cap (by far the most common cause)Likely
Cracked or damaged fuel filler neck or cap sealCommon
Loose or damaged EVAP hose near the tankCommon
Faulty fuel tank pressure sensorLess often

How to diagnose & fix

Work through it in order

Remove and reseat the fuel cap firmly until it clicks; replace it if the seal is worn or cracked.
Drive several complete cycles so the monitor can re-run, then see if the code clears.
Inspect the filler neck and cap seal for cracks or debris.
Check the EVAP hoses near the tank for looseness or damage.
If it persists, have the EVAP system smoke-tested to pinpoint the leak. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0457?+

Yes. It only affects fuel-vapor containment and emissions — nothing that impairs how the car drives.

Can I just clear P0457?+

Tighten or replace the cap first, then clear it. If the cap wasn't the problem it will return until the actual leak is fixed.

Read & clear P0457 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX