Cessna Citation pilot reported the aircraft's Collins Fusion system localizer sensing and coupling system failed; resulting in flying through the localizer. Reporter stated they have had ongoing issues with the system's localizer sensing and a lack of avionics support.

Narrative

On approach to Runway 34L I had a LOC/coupling failure. My instruments would not couple with LOC. I received vectors to LOC and needles did not indicate couple. I know the frequency was correct because I had glide slope indication. Then I was given a frequency change to Tower and got the wrong frequency (132.6 instead of 132.65; I believe this is what I read back). Prior to event I was on the NORDK6 arrival and was cleared direct to CARTR; deleting LHO crossing FL190. I was too close to comply. The frequency was busy and I tried to notify ATC that I was too close to make altitude. They gave me an alternative altitude and was told my runway would be 34L with Runway 35 on request. Normally going in there you almost always get 35 (accepted GA runway) landing north. Being prepared for both (either) is no easy task. I flew the arrival without incident and was prepared for 34L. Was cleared to intercept the LOC and it did not couple. I realized right away I was flying through the LOC and got vectors to the west. Heading 320. The computer does not respond to turns immediately and it was changing direction when I was asked again to make my turn immediately. It did not couple going the other way across the LOC. I had the incorrect frequency for tower and went back to last assigned and was cleared to land. No further incident or direct conflict noted; normal landing.I have noted intermittent issues with my LOC sensing. The panel is Collins Fusion and has occasional glitches. There is a new software/firmware package that is supposed to remedy some if not all noted issues. I have had this panel since 2018 and have adapted well. I have squawked this issue multiple times and have had it looked at twice. While in for diagnostics the facilities could not replicate the problem and they have indicated it is very hard to find an intermittent problem of this type. To the best of my knowledge they have not flown the plane to try to duplicate the issue and have used only ground equipment to diagnose. There is a new software/firmware available to install that should (according to Collins) remedy some problems and incorporate new features. As a quick side note; the Fusion division of Collins has been bought out since we installed our avionics package and the help has been moved substantially. I have lost my regional representative at least twice plus we had COVID make an influence. I have an appointment to have the software/hardware package installed. I also have documentation that I have inquired as to the nature of the LOC issue prior to this event. It is rare to happen and has never caused me to have a potential pilot deviation report. SLC with parallel runways is a difficult environment. If I were to change anything there I would not indicate to the pilots there is another runway 'on request'. Give the expected runway and do not change it. When we program our computers it is necessary to have a specific runway and 'landing north' is not an option in our programming list. It MUST be to a certain runway. That runway should remain the landing runway unless you can make a visual approach. I know they're trying to make it easier but in effect; it makes it more difficult.I do not believe this was caused by ATC/approach; nor do I believe I induced this problem. I also believe the event was handled professionally by ATC and the pilot. I have attended re-currency class.