Code P0229 power-train

I was trying to find some information on this code, I have no drivability issues.

I took a look at some live data and noticed that the long term fuel trim was around 16%
and short term was at around 0%.

I am not sure if it relates to the issue I inspected hoses around the engine for cracks and looseness found nothing.

I checked gas fill area the car does not have a gas cap it is a valve type, but it is clean of debris and nothing is keeping that valve open.

Any one familiar with this code?