The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P0446.
DTC/P0446·BMW
P0446 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Low SeveritySafe to drive (short-term)BMW
P0446 on a BMW means the ECU has detected a problem with the EVAP vent control circuit. The vent valve controls airflow through the charcoal canister that captures fuel vapours. When the valve or its circuit fails, the EVAP system cannot properly purge or seal, triggering this code.
Typical repair cost, all makes€10 - €450
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Get Skanyx freeWhat does P0446 mean on a BMW?
BMW 3 Series
2006-2024BMW EVAP systems are more complex than most, with multiple valves and a fuel tank leak detection pump. P0446 on a BMW may also involve the leak detection pump or its associated wiring. The charcoal canister and vent valve are typically accessible from under the rear of the car. BMW-level diagnostic software shows more detailed EVAP test results than a generic OBD2 reader.
What causes P0446 on a BMW?
Beyond the generic causes listed on the main P0446 page, these are the patterns noted for BMW models:
BMW 3 SeriesLeak detection pump involvement in EVAP circuit on BMW
BMW 3 SeriesComplex multi-valve EVAP system requires BMW-specific diagnostics
How to diagnose P0446 on a BMW with OBD2
Follow these steps to pinpoint the root cause of P0446:
- Rule out the fuel cap quickly: tighten it and clear the code. A cap more often sets leak codes than P0446, so if the code returns, move on to the vent valve and its circuit
- Locate the EVAP vent valve (usually near the charcoal canister, rear of vehicle or near fuel tank)
- Command the vent valve closed with a diagnostic tool that supports actuator tests (on many cars this needs manufacturer-level software rather than a generic OBD2 reader) and listen for a click. No click means the solenoid has failed or has no power
- Check wiring and connector at the vent valve for corrosion, damage, or rodent chew marks
- Inspect the vent hose from canister to vent valve for kinks, cracks, or blockage
- Check the vent filter (if accessible) for debris or spider web blockage
How much does P0446 cost to fix on a BMW? (EUR)
Estimated repair costs for P0446 in EUR, compiled across makes. Expect BMW 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 P0446
These codes are often seen alongside P0446 or point to related issues, on any make:
Looking for the full P0446 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0446 guideSkanyx · BMW
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