Problem with BMW R1100RS with ABS

After hibernation I had to buy the bike a new battery because the old one didn’t want any more. I noticed after the installation that the ABS kept flashing…., well, it used to do so several times before, when the battery was not fully charged. In the meantime also had to go to the TÜV, which refused me the stamp, however, because my ABS lamps kept flashing. Meanwhile, I also had a few meters m but my ABS still doesn’t want to. But now to my problem: I found out tonight that my ABS works when I push my motorcycle! Yes, you read right, have pushed my motorcycle on the mountain and look, ABS checkers are out. Can anyone help me? I don’t understand that. Thanks Klaus