ABS lamp

Hello together…. Unfortunately, I can’t solve my ABS problem….Let’s go with it that the ABS light didn’t go off….We soldered the control unit first and then at least a few weeks was quiet and there was TÜV…. Then the light started to light up again and we soldered again and replaced the control unit even with another……That helped but also unfortunately nothing…. Now I have the second used control unit installed (without Tracs, but no matter) and the light is still on…. What is it about?! I have the impression that the large or the small plug has a wobbler….Today on the highway the light was off once 150km and then it went on again….Before I had pulled off the plug and put something on it “played” / plugged in…… the big plug is on you or is sitting on it quite loosely? The one of the sensors is defective, can’t actually be, because it was already measured in the factory stat… Who has an idea?