
I only just realized the other day that the 1998 model years are already going to be hitting the roads out here so I figured it was my duty to inform at least everyone here about the new rules and regulations that have come into effect as of Jan 1st 2013.
The most crucial update is in the types of tests that are performed. It used to be that all 2wd or selectable 4wd gasoline/propane fueled cars got a 25/25 dyno test (25MPH with a 25% simulated load) followed by an idle test. The exhaust would be probed during the test and the readings would be compared to manufacturer's specs with tolerances set by the government.
Full time 4wd vehicles got a "two speed idle" test, where the car would be revved at idle to 2500rpm for 90secs and then at idle rpm for 90secs. Just as with the dyno test, the exhaust would be probed and readings compared to specs.
Diesels on the other hand got away with just a visual inspection, where the exhaust would be observed for 5mins at idle, and if smoke was visible for a total of 5secs at anytime during the 5mins the vehicle would fail.
THIS IS NO LONGER!!!
The government has now taken advantage of current OBDII standard systems, thus causing many different testing scenarios.
All passenger vehicles since 1997 have been standardized with OBDII diagnostic systems that allow the car's computer to be "scanned" for information and error reports (codes) by diagnostic equipment.
For the emissions tests, all vehicles (BOTH GASOLINE AND DIESEL) model year 1998 or NEWER are required to have an OBDII Test performed. *NOTE - some exceptions apply.
The test comprises of plugging the Drive Clean Test Unit into the car's computer while the car is running. The Test Unit will cross reference the entered vehicle information with the information on the car's computer to prevent tampering/cheating. Once that is done it will check for error codes in the computer, quite simply, if there are codes stored in the car's computer it will fail the test. After checking for codes the Test Unit will check the monitors (the car's computer's checklist of emissions control systems), if there is more than 2 (model years 1998-2000) or 1 (model years 2001-current) "not-ready" or "not run" monitors the car will fail. This prevents you from simply clearing the stored codes before running the test.
Exception #1 - The bigger diesel fueled vehicles (GVWR 3850kg-4500kg) Model year 2005 or OLDER are not equipped with the same emissions monitoring systems as other OBDII vehicles, therefore they are given a visual test just like before.
Exception #2 - If a vehicle fails for "not-ready" monitors it will be given a second chance (there is a process that needs to be run first), if the vehicle still fails for "not-ready" monitors AND the test is required for an ownership transfer then a "two speed idle" test will be performed.
So to summarize, if your vehicle is model year 1998 or newer, and has a MIL (Check engine light) illuminated, then it will fail the test.
Now, for the rest of us with old vehicles...
If you have a model year 1997 or OLDER gasoline powered vehicle your car will be subjected to a two speed idle test no matter what drive train type.
If you have a model year 1997 or OLDER DIESEL powered vehicle your car will be subjected to the same visual inspection as before

So... I hope you guys can make sense of this. TBH I don't know if the 1998 model year JDM vehicles are even equipped with OBDII (I would think so, but I don't know for sure).
If you guys have any questions please ask. I am a licensed Drive Clean inspector so I'm not just talking out my @$$ here, and if I don't have an answer for you right away I do have all the connections to find out for you!