P0446 Code: EVAP Vent Control Circuit
P0446 means a fault in the EVAP vent valve/control circuit — the valve that lets the charcoal canister breathe.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $60 – $400
- Time to fix
- 1-3 hours
What it means
Common causes are a stuck or dirty vent valve (often clogged with dust/debris), or wiring/connector faults. This is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle — cars, trucks, and modern fuel-injected motorcycles — from any manufacturer (Toyota, Honda, Ford and the rest). Read it with any OBD-II scanner; the meaning is the same across brands, though the exact repair can vary by engine.
Symptoms
- Check engine light on
- Usually no drivability symptoms
- Possible fuel-fill difficulty
How to fix it
- 1
Inspect the vent valve
1. Locate the EVAP vent valve (near the charcoal canister). 2. Check it for debris and test its operation and wiring. 3. Replace if stuck/faulty, then clear the code.
Frequently asked questions
Is P0446 serious?
Not for engine health — it’s an emissions/venting issue. But it can cause slow fuel filling and will fail emissions, so it’s worth fixing.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.