In your situation I'd just buy a replacement, like this:
https://www.ebay.co.uk/itm/BMW-7-SER...wAAOSwccdcjr2b and see if the problem goes away.
And then get yourself a copy of Toaf (use the search on here) and visit either
https://www.facebook.com/groups/1800705170206717/
or
https://www.facebook.com/groups/153448372029381/
Regards
Ps. Just re-read - you changed the ABS unit, there are ABS units with / without traction control, I hope you got one with the same numbers as the ABS originally had