Share a caseSign in
EmissionsSeverity Low: usually safe to drive

P0446Evaporative Emission System Vent Control Circuit

What it means

The ECU sees a fault in the canister vent valve circuit, or the vent doesn't behave as commanded.

Symptoms

  • Check engine light
  • Possibly a fuel smell
  • Usually no change in how the car drives

Common causes

  • Faulty vent valve (often blocked by dirt)
  • Wiring fault
  • Blocked vent filter or hose

What to check first

  1. Measure the vent valve resistance and run the actuator test
  2. Check the vent hose and filter for dirt or spiders
  3. Check the wiring near the tank
Can I drive with P0446? Usually yes. P0446 rarely affects how the car drives, but it keeps the check engine light on and can fail an emissions test.

Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.

Cases with P0446 (0)

Share yours

No published cases with this code yet.

Colleagues asking about P0446

Ask for help

Stuck on P0446? Describe what you measured and ask the community.

P0446: questions and answers

What does P0446 mean?

P0446: Evaporative Emission System Vent Control Circuit. The ECU sees a fault in the canister vent valve circuit, or the vent doesn't behave as commanded.

What are the symptoms of P0446?

Check engine light. Possibly a fuel smell. Usually no change in how the car drives.

What causes P0446?

Faulty vent valve (often blocked by dirt). Wiring fault. Blocked vent filter or hose.

How do you diagnose P0446?

1. Measure the vent valve resistance and run the actuator test 2. Check the vent hose and filter for dirt or spiders 3. Check the wiring near the tank

Can I drive with P0446?

Usually yes. P0446 rarely affects how the car drives, but it keeps the check engine light on and can fail an emissions test.