Mercedes C180 Kompressor ODB 2 P0170 & P171 errors

Recently been having problems with my 2004 Mercedes C180 Kompressor. It was driving well, sometimes at stoplights, it would rev inconsistently but would only be only a few 100 rev/min. This wasn’t a major problem for me at the time. Check engine light comes on months later, decided to get an ODB 2 display to see what the check engine light is. I have three errors but I think one is irrelevant to this problem. The errors I have are P0170, P0171 & P0620.

P0170 – Fuel Trim Bank 1

P0171 – System Too Lean Bank 1

P0620 – Generator Control Circuit (Alternator problem?)

Using the ODB connector I tried to look at the STFT and the LTFT. SHRTFT12 is static at 99.2% and SHRTFT1 is set to 0% no matter what the condition is. Is the problem with my sensors as it’s not producing data or is it more of a fuel problem?

There are no visible cracks in the intake system that I can see and MAS works and goes up when revs go up and go to steady-state value at idle revolutions.

Any help is greatly appreciated.