P0446: Evaporative Emission System Vent Control Circuit Malfunction
The EVAP vent valve, which lets the canister breathe, isn't working right.
Green, yellow, red: three ways P0446 can look
The same code can be a quick fix or a reason to pull over. Match your situation to the closest example.
Keep an eye on it
Light on, nothing else.
Schedule a repair
Hard to fill the tank. Schedule the repair.
Stop and get help
Fuel smell or tank pressure hissing hard when the cap is removed. Get it checked.
Symptoms you might notice
- Usually none
- Sometimes hard to fill the tank or the pump keeps clicking off
Common causes, cheapest first
- Stuck or failed vent valve
- Clogged canister or vent filter (dirt, spiders)
- Wiring problem
What you can check before calling
- Notice whether the fuel pump nozzle keeps clicking off when filling
A code points to a system, not a part. Replacing parts based on the code alone is how people spend money without fixing the problem. Testing confirms the cause first.
Want the full story? Read our guide: Check engine light after getting gas? Gas caps and EVAP codes.
Generic codes (second character 0) mean the same thing on every vehicle. Some manufacturers add their own details, so check service information for your exact vehicle.
Related codes
More evap (fuel vapor) codes
- P0440
Evaporative Emission System Malfunction - P0441
Evaporative Emission System Incorrect Purge Flow - P0442
Evaporative Emission System Leak Detected (Small Leak) - P0456
Evaporative Emission System Leak Detected (Very Small Leak) - P0457
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off) - P0496
Evaporative Emission System High Purge Flow
Look up another code
Cummins fault code (like 1922), J1939 SPN and FMI (like SPN 3251 FMI 0), or an OBD-II code (like P0420).
Questions
What does P0446 mean?
P0446 means "Evaporative Emission System Vent Control Circuit Malfunction". The EVAP vent valve, which lets the canister breathe, isn't working right.
Can I drive with code P0446?
It depends on what the vehicle is doing. Green: Light on, nothing else. Yellow: Hard to fill the tank. Schedule the repair. Red: Fuel smell or tank pressure hissing hard when the cap is removed. Get it checked.
What causes P0446?
The most common causes are: stuck or failed vent valve; clogged canister or vent filter (dirt, spiders); wiring problem.
Is P0446 a serious code?
It can be. Fuel smell or tank pressure hissing hard when the cap is removed. Get it checked.
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