P0446: EVAP System Vent Control Circuit
GarageDex's OBD-II reference explains that code P0446 means "EVAP System Vent Control Circuit" - A fault in the EVAP vent valve or its circuit - the valve that lets the charcoal canister breathe. The canister and vent valve sit under the vehicle and can get clogged with dirt/spiders.
Low - safe to drive, fix at your convenience
Safe to drive; emissions-only.
Symptoms
- Check-engine light
- Rarely a fuel-vapor smell
Common causes (most to least likely)
- Faulty vent control valve
- Clogged/contaminated charcoal canister
- Wiring or connector fault at the valve
How to fix P0446
- Inspect and test the vent valve
- Check the canister and wiring
- Replace the vent valve if it fails its test
Guidance only - confirm the cause with a scan before replacing parts. Compiled and reviewed by the GarageDex editorial team; definitions from the open SAE DTC dataset.
Tools & parts for P0446
Confirm the cause before you buy anything - a code points to a system, not a guaranteed part. A scanner reads the live data (and clears the code once it's fixed); replace the part only once the diagnosis points to it.
As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
Frequently asked
What does the P0446 code mean?
GarageDex's OBD-II reference explains that code P0446 means "EVAP System Vent Control Circuit" - A fault in the EVAP vent valve or its circuit - the valve that lets the charcoal canister breathe. The canister and vent valve sit under the vehicle and can get clogged with dirt/spiders.
What are the symptoms of P0446?
Common symptoms: Check-engine light; Rarely a fuel-vapor smell.
What causes a P0446 code?
The common causes, most to least likely: Faulty vent control valve; Clogged/contaminated charcoal canister; Wiring or connector fault at the valve.
Is it safe to drive with a P0446 code?
Safe to drive; emissions-only.
How do I fix a P0446 code?
Inspect and test the vent valve Check the canister and wiring Replace the vent valve if it fails its test Confirm the cause with a scan before replacing parts.