2012 Mercedes-Benz P0446: What It Means & Is It Safe to Drive?
P0446 on the 2012 Mercedes-Benz: Evaporative Emission System Vent Control Circuit. Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
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 on the 2012 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 2012 Mercedes-Benz, repairs for P0446 typically fall between $150 and $450, depending on the root cause and labor rates in your area.
Known issues on Mercedes-Benz
Mercedes P0446 EVAP vent control fault typically involves the carbon canister vent solenoid or the leak detection pump. Use XENTRY diagnostics to command the vent valve before replacing parts—Mercedes EVAP system faults often require dealer-level diagnostics to properly isolate.
Most commonly affected models