What causes P0446?
Code P0446 is set when the car’s computer believes (either correctly or incorrectly) that there’s a problem with the vent valve. Some systems use vacuum pressure readings to judge vent valve performance. As such, in some cases, parts that might surprise you can trigger the code.
Can a bad gas cap cause P0446?
A broken, damaged, or improperly installed gas cap most commonly raises the P0446 code. However, other, less common causes can also arise.
