You really have to remove the disc but the hub is favourite for the ring corroding and giving that fault.
Part no:- 1T0 598 611 subject to year and diameter remark if it's the hub!
Price TPS £130.39 inc vat but full retail.
Sensor part No :- 1K0 927 807 - supersession to WHT 003 859 - price TPS £72.95