Can anyone tell me what is involved in an Utah emissions/smog check for diesels?

Specifically Utah, Salt Lake, Davis and Weber counties.

On the state website it indicates that diesels 1997 and newer with GVW of 9500 lbs or less need to be checked, but it doesn't say what a check is.

If a truck is obviously missing parts, but no CEL and no visible emissions, will it pass?

Do they do a visual check for a DPF and EGR?

Do they do a sniffer test to verify all the original parts are working properly?

I'm looking at moving to one of those counties and am curious about how the smog check works.

TIA!