Evaporative emissions (fuel vapor)
P0446
Evaporative Emission System Vent Control Circuit
The sealed system that traps gasoline fumes from the tank has a leak or a valve that isn't working.
Fine to drive
Can I keep driving? Yes, in most cases. It won't hurt the car in the short term, but get it fixed. A check engine light that's already on can't warn you about a new problem. It's safe to drive. The only effects are a faint fuel smell at most and a failed emissions test.
Common causes
- A loose, worn or missing gas cap (start here)
- A cracked hose or filler neck
- A stuck purge or vent valve
- A saturated charcoal canister, often from topping off the tank
Listed roughly from most to least likely. The same code can have different causes on different cars.
What to do
- Tighten the gas cap until it clicks. Replace it if the seal is cracked.
- Drive for a few days. The light may go out by itself.
- If it returns, have a shop smoke-test the system to find the leak.
General guidance. Your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.
Related codes
- P0440Evaporative Emission System
- P0441Evaporative Emission System Incorrect Purge Flow
- P0442Evaporative Emission System Leak Detected (Small Leak)
- P0443Evaporative Emission System Purge Control Valve Circuit
- P0449Evaporative Emission System Vent Valve/Solenoid Circuit
- P0450Evaporative Emission System Pressure Sensor/Switch
- P0451Evaporative Emission System Pressure Sensor/Switch Range/Performance
- P0452Evaporative Emission System Pressure Sensor/Switch Low
Track this automatically in Tagwell Auto
Tagwell Auto keeps your car's service dates and mileage, so when a code shows up you know what was done last. With a Bluetooth reader for the car's diagnostic port (called OBD-II), the phone app can read the code itself.