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I went for my once-every-two-years state emissions tests the other day and found out that, unlike the last one, they no longer run the car at various rpm's and measure exhaust gases. Instead, they just plug into the diagnostic data port and check for fault codes. Much less work, same charge
They did the same with the car in front of mine in line, a 1999 Nissan, so I guess this is now the standard procedure. The printout has N/A's by all the rpm/gases spaces on the sheet.
It's the on board diagnostics - two (OBD-II). It constantly monitors the emissions.
Since OBD-II computer has a memory, the emissions test checks first the ability to log an error, checks for the error, then resets it. This causes a check engine lite, which the test operator looks for to insure the bulb is not unplugged or burnt out.
If a check engine indication exists, the test would fail. Your emissions test would be a failure.
Since the advent of all wheel drive, many test facilities only can "spin test" a single axle. They may also do an idle "sniff" check.
Since the advent of all wheel drive, many test facilities only can "spin test" a single axle. They may also do an idle "sniff" check.
NO. You've got it totally backwards. You cannot spin the wheels AT ALL with all-wheel-drive....especially the way most test machines do it...on a single axle. Spin just one axle on an AWD product and you will probably trash the center differential....an expensive piece of equipment. In fact, in many areas, including my own state of VA, AWD vehicles are granted a waiver and are exempt from the roller tests because of this.....you use the tailpipe sniffer instead.