Well, crap. The sucker ran fine for over a month, and just this morning tripped that same fault. Just once. Reset and it works great. Selector fault 06. No other faults in the controller, besides the CLC selector monitoring fault (025, I think). All 3 selector boards have been changed. New clc with different chips. Good hoistway scan. Nothing wrong with the limit switches on visual inspection.

not sure if you know, the DZR switch is not part of one of the 3 selector boards you replaced, it mounts to the selector housing and then plugs into the main selector board. just checking to see if you understand that ,since you reposted the same message again. as idwt says thats probably it, can't hurt to change it.

did you change the door zone reed switch?