Fault code 65794

Hi, I recently bought an O3 FL 2.0 TSI.

For the diagnostic purpose I bought the Carista OBD ( in my country original VCDS is pretty expensive ) and the car had 3 fault codes: one for interior footweell light ( replace the light bulb , it's fine ) , one for the AC air flap motor ( need to remove the glovebox in order to see if the flap need to be replaced or it's just not in place , will do this next week ) and one that I'm condused about : 

65794 - Function restriction:
Function restriction due to low
voltage

I assume that it's the battery , it's the original one. For a couples of weeks I don't have a batery tester around , so I wonder if there are any other ways to check the battery. Or maybe someone faced the same fault code and the problem is not the battery.

Any advice would help. 

Attached are some pictures with the fault code.

Sorry for the broken English. 

Thanks ! 

Edited 6 April, 20242 yr by Andreibma