This is referring to zone 5. A fault means that the zone is open, the wire is broken, or you have a defective switch. Was this article helpful? 0 out of 0 found this helpful Facebook Twitter LinkedIn Google+ Comments 0 comments Please sign in to leave a comment. Articles in this section Honeywell Vista - Replace Carbon Monoxide Detector Batteries Honeywell Vista - Replace Glassbreak Detector Batteries Honeywell Vista - Silencing and Resetting Trouble Beeps Honeywell Vista - Replace The Backup Battery Honeywell Vista - What does "FAULT 05" mean?