IMO there are more versions of WABCO D too but the manufacturer will never give complete info, also as in the link you've posted it's about a system used for trucks, tractors and buses not for cars, the modulator is completely different than the ones used for cars and it doesnt even have shuttle valve switches, the document i've studied doesnt mention anything about blink code test only electronic diagnostic on K line, see the attached document cos that's what we have not that "meritor" WABCO which is different, on tractors. trucks and buses the ABS system has separate diagnostic link for ABS with that J1922 or J1939 interface while the car version works through OBD J1962 interface
IMO you better rest your neurons about that blink test on SLABS cos i dont think it's possible and better get it plugged in a proper tester, even multivehicle testers can read them properly but not that so cheap chinese clones like Autocom, see attachment how a serious multivehicle tester must work on it