Changing error indicator in V50

Hi, everybody, it’s about my little moose, who has been trying to drive me crazy since this morning! So, it’s a V50 Bj 2007, 2.0D Was refueling this morning and when I was rolling off the tank, the onboard computer shows a message “motor system maintenance required”…. I’m still up to the office and then bought a diagnostic device during the break to check how acute the problem is! However, he didn’t issue any error code. A nice colleague then watched t and also opened the bonnet, removed the plastic cover and made a visual inspection! bonnet closed again and see, the message had disappeared, for this now stands battery warning! We then measured the Batterie, which was at 11,8V. Sounds not bad for now. Now I searched through the net and I got on a forum entry that it could be battery or even LiMa! Has anyone ever had a similar problem?