What does P0446 mean?
There is a fault in the vent valve circuit. The vent valve opens the charcoal canister to fresh air and closes it during leak tests.
The computer tried to control the part and saw an electrical fault, usually an open circuit.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Possible fuel smell
- Hard starting after refueling (with purge problems)
- No change in how the car drives in most cases
Common causes
- Open circuit in the solenoid or its wiring
- Unplugged or corroded connector
- Blown fuse feeding the component
- Failed component
How to diagnose P0446
- Check the fuse that feeds the component.
- Measure the component's resistance and compare it with the service spec.
- Check for power at the connector with the key on, and for a broken control wire back to the computer.
- Check the fuel cap and its seal first.
- Run a smoke test, the most reliable way to find EVAP leaks.
How to fix it
- Replace the fuel cap
- Replace cracked hoses
- Replace the purge or vent valve
- Replace the charcoal canister or filler neck
Estimated repair cost
Likely repairs for P0446 run from about $100 to $400, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| EVAP vent valve/solenoid | $100 - $350 |
| Wiring/connector repair | $100 - $400 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0446?
Low severity
Safe to drive. It will fail an emissions test until fixed.
Make-specific notes
GM trucks and SUVs
The canister vent solenoid mounted near the spare tire or fuel tank is exposed to dirt and water and is a frequent cause.
Always check open recalls and technical service bulletins for your VIN.
P0446 FAQ
What does P0446 mean?
P0446 stands for "Evaporative Emission System Vent Control Circuit". There is a fault in the vent valve circuit.
Can I drive with a P0446 code?
Safe to drive. It will fail an emissions test until fixed.
How much does it cost to fix P0446?
It depends on the cause. The likely repairs for P0446 range from about $100 to $400 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0446?
The most common causes are: open circuit in the solenoid or its wiring; unplugged or corroded connector; blown fuse feeding the component.