446 is the vent valve getting stuck open or closed. in any car in USA its at the back of the car near the fuel tank or on the tank. Its a pretty common failure on GM vehicles, you can look at those to get an idea of what you are dealing with.

Then you can dig into your vehicle to identify the bits n pieces and resolve it.

This can also be a tank pressure sensor failure (look at the freeze frame data to see when the fault occured)

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)