P0446: Evaporative Emission System Vent Control Circuit

P0446 is a evap system-related diagnostic trouble code classified as low severity. When your vehicle's ECU detects this condition, it stores P0446 and illuminates the check engine light.

If your vehicle has triggered P0446, you may notice one or more of these symptoms:

• Check engine light illuminated
• No noticeable driveability symptoms
• May fail emissions test
• Possible faint fuel smell near the rear of the vehicle
• Fuel tank may not pressurize correctly during EVAP self-test

Here are the most common causes of P0446:

Generally yes, for short-term driving. Completely safe to drive. The EVAP system controls fuel vapour emissions and has no effect on engine performance or safety. The consequence is a lit check engine light, which can be recorded as a deficiency at a periodic inspection.

Follow these steps to pinpoint the root cause of P0446:

1. Rule out the fuel cap quickly: tighten it and clear the code. A cap more often sets leak codes than P0446, so if the code returns, move on to the vent valve and its circuit
2. Locate the EVAP vent valve (usually near the charcoal canister, rear of vehicle or near fuel tank)
3. Command the vent valve closed with a diagnostic tool that supports actuator tests (on many cars this needs manufacturer-level software rather than a generic OBD2 reader) and listen for a click. No click means the solenoid has failed or has no power
4. Check wiring and connector at the vent valve for corrosion, damage, or rodent chew marks
5. Inspect the vent hose from canister to vent valve for kinks, cracks, or blockage
6. Check the vent filter (if accessible) for debris or spider web blockage

Repair costs for P0446 vary depending on the root cause and your vehicle. Here are typical estimates:

P0446 behaves differently depending on your vehicle. Select your car below for model-specific causes and known issues:

These codes are often seen alongside P0446 or indicate related issues: