P0446 indicates that the evaporative emission control (EVAP) system vent valve is malfunctioning. The EVAP system works to prevent fuel vapours from escaping into the atmosphere. The vent valve allows fumes to enter into the system and flow to the charcoal canister, where they are absorbed and stored. The engine control module performs a leak test while the vehicle is switched off. To do so, it closes both of the EVAP valves to keep fumes sealed inside. If the module detects a short circuit when trying to activate the vent component, or the EVAP pressure is not maintained, it will trigger this code.
Possible causesIt indicates that there’s a problem with the EVAP vent valve or a leak in the system, causing a drop in pressure.
The symptoms of P0446 are not normally serious or particularly noticeable when driving. However, it is better to have your vehicle inspected and repaired to avoid a more serious issue and improve the vehicle’s fuel economy.
This is possible if the DTC was triggered due to something simple like a loose petrol tank cap of the car. After fixing the problem, the error should be cleared automatically after several normal test cycles.
Fault code P0446 - Evaporative Emission Control System Vent Control Circuit Malfunction can occur with any car but is most often found on the following cars:
If you get the code P0446 on your car, make sure that the diagnostics are carried out correctly and the error is still relevant. Check for symptoms associated with the problem and explore options for resolving it.
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