In nevada every year you have to go to a smog station (private owned). There is a check list the huy goes through like fuel cap, pcv valve, vacuum hoses not plugged off, muffler & cat in place etc. gas engine rigs just sits parked but diesel is up on dyno rollers to load the engine. Then they plug into obd2 and run it at idle a little, then at speed, something like 35-40 mph on the dyno- gas engine just rev it up and hold around 3,000 rpm.
Older cars that don’t have obd2, that just have a probe in the tail pipe and it monitors parts per million of nox, carbon monoxide, hydro carbons, oxygen. Also noting if too much visible smoke comes out. There is an optic tester if too much smoke, but that is almost never used.
Because obd2 can have codes be reset, it has to be in the ready state. You can’t just clear the codes- you have to complete the drive cycle for them to be gone legitimately. Trouble codes related to emissions are automatic failure.
So the moment you have an obd2 rig, it has to have emissions read through the ecm. This was the entire purpose the ds4 was built. A creative individual could get away with removing the obd2 plug and installing an obd1 in its place- then they would do the tail pipe test, which any db2 truck even with blowby passes no problem. But the computer system knows that gm trucks had obd2 before the 1996 mandatory year. I forget what hear it is 1994 that gm had obd2 and ds4 in all their trucks? So when you are missing the required obd2 ability to monitor emissions here- automatically fail.
My hummer is a 95. The last year of hummer obd1 with db2. Wanna guess why it was specifically chosen even though they were n/a and turbo only option on ds4 hummers?
So you go pay the smog inspection owner each year (now like $84) it takes about 15-20 minutes plus waiting in line sometimes for an hour, usually 15 minute wait, and they gove you a slip of paper saying you passed. The computer is linked to dmv, so you can either go in person with the paper or go online and type in your information along with a big serial number of that inspection that just happened and pay with a card that years registration fees. A late 90’s diesel pickup is probably in the $55 dollar range is my guess. Used to be about $40. This is on top of the smog fees set by the county. Smog fee is maybe $20 less in Northern county where Reno is but registration is same. Then extra for personalized plates if you want them.
I will let others from NY, Ca and Az
@WarWagon tell theirs because it might have changed since ai last seen their system.
