check and clean the abs sensors, not sure where they are but will try to find out over the next few days, weathers too bad for me to get under the van. Probably attached to the brakes somewhere, remove the wheels, and get the brake shoes as clean as possible,
dont rush to MB just yet.
Had a look today.
Think this might be the abs sensor on the front left.
Remove the screw and clean up the connections. Lets know of any change.