My 92 Buick Park Avenue did this once. The "anti-lock" light stayed on for a while longer than it should have a few weeks ago. Now the light goes just a few seconds after start-up. I guess it was a temporary malfunction, but I still have no idea what. I posted about it on a Buick site, similar to this site and someone said that the computer will store a code as to what the problem was. This is for GM cars however - I am not sure if Mercedes would store a code or not. Be worth a try to find out before you replace all sorts of parts. Good luck.
1993 Mercedes 400SEL 4dr
2012 Honda Civic LX 4dr
1972 Chevrolet Caprice Kingswood Estate 9-passenger wagon
1973 Pontiac Grand Ville 4-dr hardtop sedan
1988 Mercedes 300SEL (was mine, now mothers)