P0457 on Ford
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
P0457 on Ford vehicles indicates evaporative emission system leak detected (fuel cap loose/off). Au7o has documented this code across 2 Ford models — most commonly on Fiesta, Mustang. This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. Typical repair costs on Ford range from $30 to $1,800, depending on the specific model and root cause.
Common Causes of P0457
- •Loose, missing, or improperly tightened fuel cap
- •Worn or cracked fuel cap seal/gasket
- •Damaged fuel filler neck or sealing surface
- •Cracked or disconnected EVAP hose
- •Stuck-open purge or vent valve
- •Faulty fuel cap that won't hold pressure
- •Leaking charcoal canister
P0457 on Ford by Model
Ford Fiesta(1 issue)
- EVAP Canister Purge Valve Failure2011-2019
The EVAP canister purge valve sticks open, causing difficulty fueling (pump nozzle keeps clicking off), rough idle, and check engine light. Very common on the 1.6L engine.
Ford Mustang(1 issue)
- Fuel Tank Cracking and Fuel Vapor/Fuel Leak at Tank Seam or EVAP Area2005-2010
S197 Mustangs from the mid-2000s have a documented pattern of fuel tank cracking or leaking, often near the seam or around the evaporative emissions components. Owners report strong fuel odor in garages, visible dripping after fill-ups, and EVAP-related warning lights. Because the issue involves fuel leakage near the rear of the vehicle, it presents a fire risk and can require full tank replacement.
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View P0457 across all makes →Frequently Asked Questions
What does P0457 mean on Ford?▼
P0457 stands for "Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)." This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. On Ford specifically, this code is documented across 2 models.
What causes P0457 on Ford vehicles?▼
Common causes on Ford: Loose, missing, or improperly tightened fuel cap, Worn or cracked fuel cap seal/gasket, Damaged fuel filler neck or sealing surface, Cracked or disconnected EVAP hose, Stuck-open purge or vent valve. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0457 on a Ford?▼
Repair costs on Ford range from $30 to $1,800, depending on the specific model and root cause.
Which Ford models have P0457 documented?▼
Au7o has documented P0457 on 2 Ford models: Fiesta, Mustang.