There may not be a NOTAM if the failure/downgrade only happened a sort while ago!
If the checks/test for the equipment on that day return a degraded state of operaion (system redundancy, lighting unserviceabilities etc) then the ATIS will have to broadcast the capabilities and limitations of the system.
Those limitations then become the absolute minima until the fault is cleared.
In short, if an airfield broadcsts for eg. ILS Cat 2 only - that (or your company approved cat 2 minimum) is your limit.