P0456 means the engine control unit has detected a very small leak in the evaporative emission control system - smaller than 0.020 inches (0.5mm). This is the smallest leak the OBD-II system can detect. The cause is almost always a fuel cap that was not tightened to the full click, a hardened cap rubber seal, or a hairline crack in a vapour line.
Geschätzte ReparaturkostenVon €10 bis €550+, je nach Fahrzeug
Was bedeutet P0456?
P0456 means the engine control unit has detected a very small leak in the evaporative emission control system - smaller than 0.020 inches (0.5mm). This is the smallest leak the OBD-II system can detect. The cause is almost always a fuel cap that was not tightened to the full click, a hardened cap rubber seal, or a hairline crack in a vapour line.
P0456 ist ein evap-system-bezogener Diagnosefehlercode mit dem Schweregrad low. Wenn das Steuergerät Ihres Fahrzeugs diesen Zustand erkennt, speichert es P0456 und aktiviert die Motorkontrollleuchte.
Was sind die Symptome von P0456?
Wenn Ihr Fahrzeug P0456 ausgelöst hat, bemerken Sie möglicherweise eines oder mehrere dieser Symptome:
Check engine light on (often the only symptom)
Occasional faint fuel odour near the rear of the car, especially in warm weather
Fuel cap warning indicator on some vehicles (Ford, GM)
No driveability issues, normal fuel economy
Code may come and go between drive cycles before setting permanently
Was verursacht P0456?
Hier sind die häufigsten Ursachen für P0456, geordnet nach Wahrscheinlichkeit:
hochFuel cap not tightened to the full click after refuelling
hochHardened or cracked rubber seal on the fuel cap
mittelHairline crack in an EVAP vapour line, often where it bends near the fuel tank
mittelPurge or vent valve with a leaking internal seal (not stuck open, just weeping)
niedrigCracked or porous charcoal canister
niedrigLeak at the fuel filler neck rubber gasket
Kann man mit P0456 weiterfahren?
Im Allgemeinen ja, für kurze Strecken. A very small EVAP leak does not affect engine performance or safety. You can drive normally, but the check engine light will trigger an automatic fail at any EU vehicle inspection (TÜV, ITV, TA, SKP, MOT) until it is fixed.
Wie diagnostiziert man P0456?
Befolgen Sie diese Schritte, um die Grundursache von P0456 zu ermitteln:
Tighten the fuel cap until you hear three clear clicks. Clear the code and complete three full drive cycles (cold start to full operating temperature, then cool down) before checking if it returns. EVAP monitors only run under specific temperature and fuel-level conditions
Inspect the fuel cap rubber seal. If the seal is dry, glossy, cracked, or has lost flexibility, replace the cap. A worn seal is the second most common cause of P0456 after a loose cap
Perform a smoke test on the EVAP system with the fuel cap installed. A very small leak will appear as a faint, slow plume of smoke. Focus on hose connections, the purge and vent valve bodies, and the canister housing
Use a propane enrichment test on suspect joints. With the engine idling, slowly direct propane near each EVAP component. If the engine RPM rises, propane is entering through a leak
Command the purge valve closed with a bidirectional scan tool and pull vacuum on the EVAP system. The valve should hold vacuum for at least 30 seconds. A slow leak past the valve seat is a common P0456 cause
Test the vent valve in the same way. The vent valve must seal completely during the EVAP self-test. A weeping vent valve seal will not stick open enough to cause P0446, but is loose enough to fail the very small leak threshold
Was kostet die Reparatur von P0456?
Die Reparaturkosten für P0456 variieren je nach Grundursache und Fahrzeug. Hier sind typische Schätzungen:
Reparatur
Teilekosten
Arbeitskosten
Gesamtschätzung
DIY-Schwierigkeit
Replace fuel cap
€10–€40
€0–€0
€10–€40
Einfach
Replace a cracked EVAP vapour line section
€15–€60
€40–€150
€55–€210
Mittel
Replace purge valve
€25–€120
€40–€150
€65–€270
Mittel
Replace vent valve
€30–€130
€60–€200
€90–€330
Mittel
Replace charcoal canister
€70–€300
€80–€250
€150–€550
Mittel
Preise geschätzt, Stand March 2026. Kosten variieren je nach Region, Fahrzeug und Werkstatt.
P0456 bei bestimmten Fahrzeugen
P0456 verhält sich je nach Fahrzeug unterschiedlich. Wählen Sie unten Ihr Auto aus, um modellspezifische Ursachen, bekannte Probleme und angepasste Kostenschätzungen zu sehen:
P0456 beim BMW 3 Series
BMW 3 Series • 2006-2024
BMW 3 Series and 1 Series with the DMTL pump (Diagnostic Module Tank Leakage, fault code 2A17 on the BMW side) commonly throw P0456 when the DMTL pump motor or its rubber filter fails. The pump is mounted near the charcoal canister and is exposed to road debris. Replacement of the entire DMTL module is the typical fix. Fuel cap is rarely the cause on modern BMWs because the cap is integrated and tamper-resistant.
Was verursacht P0456 bei einem BMW 3 Series?
BMW 3 SeriesDMTL pump motor or rubber filter failure (BMW fault code 2A17)
BMW 3 SeriesCracked EVAP line near the fuel filler neck
Reparaturkosten für P0456 beim BMW 3 Series
Geschätzte Kosten für BMW 3 Series-Besitzeraufgrund BMW-spezifischer Teilepreise höher als der Durchschnitt
Reparatur
Teilekosten
Arbeitskosten
Gesamtschätzung
DIY-Schwierigkeit
Replace fuel cap
€13–€52
€0–€0
€13–€52
Einfach
Replace a cracked EVAP vapour line section
€20–€78
€52–€195
€72–€273
Mittel
Replace purge valve
€33–€156
€52–€195
€85–€351
Mittel
Replace vent valve
€39–€169
€78–€260
€117–€429
Mittel
Replace charcoal canister
€91–€390
€104–€325
€195–€715
Mittel
Preise geschätzt, Stand March 2026. Kosten variieren je nach Region, Fahrzeug und Werkstatt.
P0456 beim Volkswagen Golf
Volkswagen Golf • 2005-2024
The Golf shares EVAP architecture with the rest of the VAG range. The N80 purge valve is the most common P0456 trigger on Mk6, Mk7, and Mk8. On the 1.2 TSI and 1.4 TSI engines, the valve weeps internally rather than sticking, so it tests fine with a multimeter but fails a vacuum hold test. The fuel cap on Mk7+ is integrated with the filler neck and rarely causes leaks.
Volkswagen GolfCracked carbon canister housing on Mk6
Reparaturkosten für P0456 beim Volkswagen Golf
Geschätzte Kosten für Volkswagen Golf-Besitzeraufgrund Volkswagen-spezifischer Teilepreise höher als der Durchschnitt
Reparatur
Teilekosten
Arbeitskosten
Gesamtschätzung
DIY-Schwierigkeit
Replace fuel cap
€12–€46
€0–€0
€12–€46
Einfach
Replace a cracked EVAP vapour line section
€17–€69
€46–€173
€63–€241
Mittel
Replace purge valve
€29–€138
€46–€173
€75–€311
Mittel
Replace vent valve
€35–€150
€69–€230
€103–€379
Mittel
Replace charcoal canister
€81–€345
€92–€288
€173–€633
Mittel
Preise geschätzt, Stand March 2026. Kosten variieren je nach Region, Fahrzeug und Werkstatt.
P0456 beim Toyota Camry
Toyota Camry • 2007-2024
Toyota EVAP systems set P0456 most often from a loose or hardened fuel cap. The 2007-2017 Camry uses a screw-on cap that is particularly sensitive to seal age - replace the cap every 4 to 5 years preventively. From 2018 the Camry switched to a capless filler that eliminates this failure mode entirely.
Was verursacht P0456 bei einem Toyota Camry?
Toyota CamryHardened fuel cap seal on 2007-2017 models
Toyota CamryCharcoal canister cracking after 200,000 km
P0456 beim Honda Civic
Honda Civic • 2006-2024
Civic EVAP systems are robust. P0456 on a Civic is most often a fuel cap issue or a cracked vapour line near the rear axle. The 2016+ 1.5L turbo has a known issue where the EVAP canister vent solenoid filter clogs with road debris, causing the valve to seal imperfectly and producing intermittent P0456 codes. Honda has revised the filter design twice.
Was verursacht P0456 bei einem Honda Civic?
Honda CivicVent solenoid filter clog on 1.5T (2016+)
Honda CivicVapour line damage at the rear axle area from underbody work
Reparaturkosten für P0456 beim Honda Civic
Geschätzte Kosten für Honda Civic-Besitzeraufgrund Honda-spezifischer Teilepreise niedriger als der Durchschnitt
Reparatur
Teilekosten
Arbeitskosten
Gesamtschätzung
DIY-Schwierigkeit
Replace fuel cap
€9–€36
€0–€0
€9–€36
Einfach
Replace a cracked EVAP vapour line section
€14–€54
€36–€135
€50–€189
Mittel
Replace purge valve
€23–€108
€36–€135
€59–€243
Mittel
Replace vent valve
€27–€117
€54–€180
€81–€297
Mittel
Replace charcoal canister
€63–€270
€72–€225
€135–€495
Mittel
Preise geschätzt, Stand March 2026. Kosten variieren je nach Region, Fahrzeug und Werkstatt.
Verwandte Fehlercodes
Diese Codes treten häufig zusammen mit P0456 auf oder weisen auf verwandte Probleme hin:
Indefinitely from a mechanical safety standpoint. P0456 only affects emissions, not engine operation. However, the check engine light will fail any EU emissions inspection. Plan the repair before your next TÜV, ITV, TA, SKP, or MOT date.
Will P0456 cause my car to fail TÜV or other EU inspections?
Yes. Every EU technical inspection regime fails a vehicle with an active check engine light, regardless of the underlying code. The pre-inspection OBD readiness check will also catch a recently cleared P0456 because the EVAP monitor takes 3 to 5 drive cycles to complete.
Will P0456 affect my fuel economy?
No, not in any measurable way. The leak is smaller than 0.5mm. The amount of fuel vapour escaping is too small to register on your trip computer. If you are also seeing reduced fuel economy, look for another cause like a faulty oxygen sensor or air leak.
Can hot or cold weather trigger P0456?
Yes. The EVAP monitor compares pressure changes in the fuel system to ambient temperature. Sudden cold snaps can shrink rubber seals just enough to leak below the small-leak threshold. Hot weather can vaporise fuel faster than a marginal canister or valve can handle. P0456 codes that appear only in winter are often a stiffening fuel cap seal.
Why does P0456 keep coming back after I tighten the cap?
Three possibilities. First, the cap seal has hardened and tightening alone is not enough - replace the cap. Second, there is a second leak elsewhere in the system that needs a smoke test to find. Third, on some Toyota and Subaru models the EVAP test parameters are sensitive enough that a slightly degraded purge valve seal will set P0456 even with a perfect cap.
Scannen Sie Ihr Auto mit Skanyx, um P0456 zu diagnostizieren
Verbinden Sie einen beliebigen Bluetooth-OBD2-Adapter, scannen Sie nach Fehlercodes und erhalten Sie KI-gestützte Diagnosen mit Schweregradbewertungen und Reparaturkostenschätzungen.
