recently i have been having issues with my car the dash ready convenient functions temporary unavailable then switches back to available vise versa i had the batteries checked rear was fine front AUX battery was low so i replaced it and the problem continued has anyone else has this issue ? its a 2005 E55 AMG car is 8 years old now i thought maybe i should jet replace the rear battery and see what happen thought i would get some opinions first. Also i have noticed my paddle shifters aren't working....

help me please

 

Could be a charging issue or an issue with the battery control module BCM. You also may have a battery draw that is draining your battery when the vehicle is off. If you have a draw, then something is drawing power from the battery and when you start the vehicle and drive, eventually you are fully charged and that is when the message will disappear. Start off with having an amp draw test performed