EMB-145 pilot reported during descent they got an amber CAS message for pressurization auto fail. They ran the QRH and manually operated the pressure controller and landed safely.

Narrative

On Day 0 (approx. XA:30 ZZZ) CA and I were descending through about FL 200 on arrival to ZZZ. Amber CAS message PRESN AUTO FAIL illuminated accompanied by a sharp sound; and sharp pressure in my ears and frontal sinus; consistent with a rise in cabin altitude. CA and I donned oxygen masks.I believe we missed a call from Center while we had our headsets off. Once masks were on and crew communication was established; I let Center know that we lost auto press and to standby a moment. The QRH directed us to put the Manual Pressurization Controller in the 11 o' clock position and activate Manual mode; which we did. Initially; manual control appeared to be possible and the cabin began descending. Thus; we did not feel it necessary to declare an emergency; but requested lower from center (and subsequently approach) as they were able to accommodate. Very shortly after; the cabin began descending very rapidly. We attempted to reduce the rate of cabin descent; but the controller did not respond appropriately; at one point continuing its descent to 1500' below sea level while aircraft altitude was 12000' MSL; hitting max differential. While being vectored for the visual; it was clear we could not land with the cabin so far below the field elevation. [The] CA and I elected to take delay vectors to continue to troubleshoot the issue. With the manual controller pegged out at the full UP position; the best we could achieve was +200 FPM up; but cabin rate continued to be erratic in both the up and down directions (at times hitting -200/+1000 FPM; all while the full up position was selected; but averaging about +200 FPM overall. Turns exacerbated the issue of the cabin descending.) Over the course of several minutes on delay vectors; the cabin finally climbed to approx. 700' below field elevation; before again descending. At this point CA and I agreed initiate the approach as it seemed the closest the aircraft achieved to ZZZ. The visual backed up by ILS XX was uneventful and concluded with a normal landing. Upon parking; we remained with door shut until Maintenance Control via telephone instructed [the] CA to crack the DV window open. I mentioned trying the Dump button to [the] CA; but the company instructed him to do it that way.In conclusion; the purpose of this Report is; in the opinion of the writer; primarily to cover any delays we may have had in responding to ATC instructions; or to explain any inconvenience this event may have subsequently created for ATC when we entered the terminal area of ZZZ; to include those delay vectors (in the event that they constituted priority handling;) and general speed fluctuations; due to the saturating; (and at times; physically painful and distracting) nature of the event. CA and I complied with all Company SOP and all manufacturers' instructions during all phases of flight; and this event concluded satisfactorily. Cause: Maintenance failure. PRESN AUTO FAIL had occurred at least three times in preceding months with increasing event severity according to Maintenance logbook; closed with the legal minimum required maintenance action. Further; contract maintenance in ZZZ determined through ground testing that the manual controller was either mis-installed; mis-calibrated; or both; as; the 11 o clock position should provide a neutral 0 cabin rate; but at that position; was commanding a rate of -2200 feet down. Ground testing further revealed the best rate MAX UP position would command was +300 FPM. Suggestions: Maintenance being more proactive when the aircraft is giving signs; instead of purely reactive when hard fails do occur.