The Quick Answer above is the generic definition. What follows is the model-specific detail for the Volkswagen models that log P0456.
DTC/P0456·Volkswagen
P0456 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Low SeveritySafe to drive (short-term)Volkswagen
P0456 on a Volkswagen 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 usual causes are a fuel cap that was not tightened to the full click, a hardened cap rubber seal, or a hairline crack in a vapour line.
Typical repair cost, all makes€10 - €550
Connect any standard Bluetooth OBD2 adapter to your Volkswagen and Skanyx tells you what P0456 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0456 mean on a Volkswagen?
Volkswagen Golf
2005-2024On Golfs with leak-detection hardware, a weeping N80 purge valve is a known P0456 trigger: it can pass an electrical test yet fail a vacuum hold test. Many European-market cars are built to EU on-board diagnostic rules, which only require the purge valve circuit to be checked rather than the system to be tested for leaks, so check that your car actually has leak-detection hardware before chasing this code.
What causes P0456 on a Volkswagen?
Beyond the generic causes listed on the main P0456 page, these are the patterns noted for Volkswagen models:
Volkswagen GolfN80 purge valve weeping (passes electrical test, fails vacuum hold)
Volkswagen GolfCracked carbon canister housing
How to diagnose P0456 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0456:
- Tighten the fuel cap until it 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 another common cause of P0456 alongside 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 diagnostic tool that supports actuator tests (often manufacturer-level software) 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 still opens and closes on command, so it sets no vent-control code such as P0446, but it passes enough vapour to exceed the very small leak threshold
How much does P0456 cost to fix on a Volkswagen? (EUR)
Estimated repair costs for P0456 in EUR, compiled across makes. Expect Volkswagen parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Codes related to P0456
These codes are often seen alongside P0456 or point to related issues, on any make:
Looking for the full P0456 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0456 guideSkanyx · Volkswagen
Diagnose P0456 on your Volkswagen
Your car logged P0456. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and shows the €10-€550 repair range so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.
Get Skanyx free