P0457: Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)
Low SeveritySafe to drive (short-term)EVAP System
P0457 means the ECU detected an evaporative system leak consistent with a loose, missing, or damaged fuel cap. The code is specifically tuned to flag cap-sized leaks before flagging generic small (P0442) or large (P0455) leaks. The first thing to check is always the cap itself.
What does P0457 mean?
P0457 means the ECU detected an evaporative system leak consistent with a loose, missing, or damaged fuel cap. The code is specifically tuned to flag cap-sized leaks before flagging generic small (P0442) or large (P0455) leaks. The first thing to check is always the cap itself.
P0457 is a evap system-related diagnostic trouble code classified as low severity. When your vehicle's ECU detects this condition, it stores P0457 and illuminates the check engine light.
What are the symptoms of P0457?
If your vehicle has triggered P0457, you may notice one or more of these symptoms:
Check engine light illuminated
Fuel cap warning indicator on some vehicles (Ford, GM, some VAG)
Faint fuel odour when stationary, especially after refuelling
Failed emissions test
No noticeable driveability issues
What causes P0457?
Here are the most common causes of P0457, ranked by how likely they are to be the culprit:
highLoose fuel cap (not tightened until click)
highWorn or cracked fuel cap rubber seal
mediumMissing fuel cap (left at fuel station)
mediumDamaged fuel filler neck seal or threads
lowCapless filler flapper not sealing (newer Ford, BMW models)
Is it safe to drive with P0457?
Generally yes, for short-term driving. P0457 is specifically a fuel cap leak code and has no effect on engine performance or safety. Tighten the cap immediately and drive normally. The check engine light will cause an automatic fail at any EU emissions inspection until the code clears.
How do you diagnose P0457?
Follow these steps to pinpoint the root cause of P0457:
Remove the fuel cap and inspect the rubber seal for cracks, brittleness, or debris. If the seal compresses unevenly when squeezed, replace the cap
Re-seat the cap and tighten until you hear at least three clicks. Clear the code and drive for 3 to 5 cycles to let the EVAP monitor retest
If the code returns with a known good cap, inspect the fuel filler neck. Look for damage to the threads or to the sealing surface where the cap meets the neck
On capless filler systems (newer Ford, BMW), inspect the flapper assembly for debris, damaged seals, or a stuck flapper. Clean carefully or replace the assembly if damaged
If the cap and filler neck are good, perform a smoke test focusing on the upper portion of the EVAP system. A leak at the tank top or fuel pump module gasket can mimic a cap leak
How much does P0457 cost to fix?
Repair costs for P0457 vary depending on the root cause and your vehicle. Here are typical estimates:
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Tighten existing fuel cap (free fix)
€0–€0
€0–€0
€0–€0
Easy
Replace fuel cap
€10–€40
€0–€0
€10–€40
Easy
Replace fuel filler neck or capless flapper assembly
€80–€300
€80–€200
€160–€500
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0457 on specific vehicles
P0457 behaves differently depending on your vehicle. Select your car below for model-specific causes, known issues, and adjusted cost estimates:
P0457 on BMW 3 Series
BMW 3 Series • 2005–2024
BMW E90 uses a screw-type fuel cap that should click multiple times when properly tightened. Newer F30 and G20 models often use a capless filler with a flapper assembly. If the flapper does not seal properly, P0457 can set even though there is no visible cap. Inspect the flapper carefully and clean any debris.
What causes P0457 on a BMW 3 Series?
BMW 3 SeriesWorn rubber seal on E90 screw-type cap
BMW 3 SeriesCapless flapper not sealing on F30/G20
P0457 repair cost for BMW 3 Series
Estimated costs for BMW 3 Series ownersadjusted higher than average due to BMW-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Tighten existing fuel cap (free fix)
€0–€0
€0–€0
€0–€0
Easy
Replace fuel cap
€14–€56
€0–€0
€14–€56
Easy
Replace fuel filler neck or capless flapper assembly
€112–€420
€112–€280
€224–€700
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0457 on Volkswagen Golf
Volkswagen Golf • 2005–2024
VW Golf uses a bayonet-style fuel cap that must be turned until it clicks. Owners frequently report P0457 after a quick refuel where they forgot to twist the cap to the click point. Replacement OEM caps from VW or aftermarket from Autodoc.de cost 15 to 30 EUR.
What causes P0457 on a Volkswagen Golf?
Volkswagen GolfBayonet cap not turned to click point after refuelling
Volkswagen GolfCracked seal on aging cap (especially Mk5)
P0457 repair cost for Volkswagen Golf
Estimated costs for Volkswagen Golf ownersadjusted higher than average due to Volkswagen-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Tighten existing fuel cap (free fix)
€0–€0
€0–€0
€0–€0
Easy
Replace fuel cap
€12–€46
€0–€0
€12–€46
Easy
Replace fuel filler neck or capless flapper assembly
€92–€345
€92–€230
€184–€575
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0457 on Audi A4
Audi A4 • 2005–2024
B7 and B8 A4 share the bayonet-style cap with the VW Golf. P0457 is one of the most common codes set on these vehicles, almost always due to operator error at the pump. Train all drivers to twist the cap until it audibly clicks at least twice.
What causes P0457 on a Audi A4?
Audi A4Bayonet cap not seated properly at refuelling
Audi A4Worn cap seal at 100,000+ km
P0457 repair cost for Audi A4
Estimated costs for Audi A4 ownersadjusted higher than average due to Audi-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Tighten existing fuel cap (free fix)
€0–€0
€0–€0
€0–€0
Easy
Replace fuel cap
€13–€50
€0–€0
€13–€50
Easy
Replace fuel filler neck or capless flapper assembly
€100–€375
€100–€250
€200–€625
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
P0457 on Ford Focus
Ford Focus • 2005–2024
Ford Focus Mk2 uses a standard screw-type cap with a tether. Mk3 introduced the Easy Fuel capless system on many European trims, eliminating the cap entirely. On capless models, P0457 typically traces to debris stuck in the flapper or a damaged flapper spring. Cleaning often resolves it.
What causes P0457 on a Ford Focus?
Ford FocusWorn screw-cap seal on Mk2 (most common cause)
Ford FocusDebris in Easy Fuel flapper assembly on Mk3 capless models
P0457 repair cost for Ford Focus
Estimated costs for Ford Focus ownersadjusted lower than average due to Ford-specific parts pricing
Repair
Parts Cost
Labor Cost
Total Estimate
DIY Difficulty
Tighten existing fuel cap (free fix)
€0–€0
€0–€0
€0–€0
Easy
Replace fuel cap
€9–€36
€0–€0
€9–€36
Easy
Replace fuel filler neck or capless flapper assembly
€72–€270
€72–€180
€144–€450
Professional
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related diagnostic codes
These codes are often seen alongside P0457 or indicate related issues:
How long does P0457 take to clear after I tighten the cap?
After tightening the cap or replacing it, the ECU needs 3 to 5 complete drive cycles to retest the EVAP system and clear the code. A drive cycle includes a cold start, mixed driving over 15 to 20 minutes, and shutdown. You can also clear it manually with a scan tool to confirm the fix immediately.
Is P0457 different from a generic EVAP leak code?
Yes. P0457 is specifically tuned to the leak size associated with a loose or missing fuel cap (typically a medium-size leak). The ECU sets P0457 rather than the generic P0455 (large leak) or P0442 (small leak) when the leak profile matches a cap-sized opening, giving the driver a more specific hint.
Why does my fuel cap warning light keep coming on?
If you've already tightened the cap and the light returns, the rubber seal is most likely worn, cracked, or contaminated with fuel residue. Replacement caps cost 10 to 40 EUR and take seconds to install. Always buy a manufacturer-spec or OEM-equivalent cap, not the cheapest universal option.
Can topping off the fuel tank cause P0457?
Yes, indirectly. Overfilling the tank past the first click of the fuel nozzle can saturate the charcoal canister with liquid fuel. A saturated canister cannot hold vacuum properly during EVAP self-tests and can set leak codes including P0457. The fix is to stop topping off and let the system self-recover over several drive cycles.
