2C57, 321C, 2BC0 Error codes

[Mido01]

I get these codes (2C57, 321C, 2BC0) with half check engine light only on highway speed when I am on an incline saying engine malfunction and reduced power but I do not notice any reduction in power. Never shows when I'm driving in the city. Sometimes (rare now) I get a message on the iDrive saying to tighten gas cap when I'm driving in the city. Only symptom I'm seeing is poor fuel economy (10 l/100 km highway and 15 l/100 km city which is about 4l/100km over advertised) and a rattle noise which I think is the wastegate because it sounds like when you stop pedaling on a bike and the bike continues to move. Turbo feels and sounds fine, it spools and feels like it gives normal power.

Could some of these codes be related to the wastegate? Could a weak battery cause any of these codes?

2C57 - Charging pressure control, plausibility Pressure too low.
321C - leak in the tank deaeration and purging air system >1mm
2BC0 - Mixture control: Mixture too lean

Additionally, I used to have these codes before I got bimmerlink and erased the codes:
2774 - Air mass, plausibility: Air mass too high.
3166 - Tank Ventilation System: Malfunction

Car: 2012 E84 28i XDrive