What does code P0446 mean on a Mercedes-Benz and is it safe to drive?
P0446: Evaporative Emission System Vent Control Circuit. Here’s what it means on your Mercedes-Benz, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
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What this code means
The PCM has detected a problem with the EVAP vent control circuit, often caused by a stuck or failed vent valve.
Common causes for your Mercedes-Benz
- Failed EVAP vent solenoid
- Corroded wiring or connector at vent valve
- Blocked vent due to dust, rust, or spider webs
Symptoms
- Check Engine Light
- Possible difficulty filling fuel tank (nozzle keeps clicking off)
Typical fixes
- Replace EVAP vent valve/solenoid
- Clean or clear vent and charcoal canister area
- Repair wiring
Repair cost range
For a Mercedes-Benz, repairs for P0446 often fall between $150 and $450, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.