Passing the emissions test

Discussion in 'Emissions' started by Toney, Dec 5, 2011.

  1. Toney

    Toney Member

    Hello. Sorry if this hasn't been answered before, but searching for a very specific question on passing an emmisions test still leaves a question:

    As long as I don't get a CEL, will I pass the emission test in a modern car? I'm worried that an emmision test examines any current and other errors "stored up". Will Scan Guage e (or any error code reader) report current AND "stored up" error codes that an emmisions test will look at? This assumes an emmisions test that isn't probing the exhaust pipe.

  2. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Yes, the scangauge will report stored and current error codes.

    It won't guarantee a pass on the exhaust gas sensor test. It can alert you to potential problems, but isn't a sure thing for pass/fail.

    I don't know of an emissions test that doesn't analyze the exhaust. I'm not sure how else you can test it.
  3. 08EscapeHybrid

    08EscapeHybrid Moderator

    I think it depends on what state you're in. Here in Virginia they only do tailpipe tests on non-OBDII vehicles. On my OBDII vehicles, the emissions test only takes about 10 minutes. On my printout its obvious that they are not doing a tailpipe test, just a computer test for stored codes.

    Here's one of the printouts from one of my OBDII vehicles past emissions tests:

  4. PaleMelanesian

    PaleMelanesian Beat the System Staff Member

    Really? Wow. I live in a non-testing area, but the cities in Texas that do test use a tailpipe sensor.
  5. Toney

    Toney Member

    Just to clarify, I've been doing a little more research. An absent CEL doesn't guarantee a pass, I've learned. But will the scan guage e return the state of "readiness flags" that are set as the car does it cycle thing?

  6. Toney

    Toney Member

    Ditto the WOW. The Virginia test looks like a straight CEL test. It seems to be testing the easy stuff that can be picked up by code reader: gas cap, catalytic converter, trouble shooting codes. Oh, and whether there is a bunch of smoke coming out the back end, visually. I suspect, though, that the test also assumes that readiness flags are set following a drive period. I mean, they figures out the trick of disconnecting the battery before taking the test.

    BTW, Washington state doesn't do a tail pipe test either.

  7. rfruth

    rfruth Well-Known Member

    I live in a city that does test and there is no tailpipe sensor used (if there is an OBD-II port) - its quite a through test, they can tell how the vehicle is doing now and how its been doing in the past - yea !
  8. 08EscapeHybrid

    08EscapeHybrid Moderator

    Yes, as you drive the computer will do a series of self tests. If you reset the codes or disconnect the battery, these tests have to be run all over again before the computer will report a ready state for emissions tests. If I recall correctly it takes 1-2 weeks of driving normally before the computer can report a ready state for emissions tests. If you disconnect the battery and take it in for an emissions test, they will tell you to come back in 2 weeks.

    For comparison, here's a test from one of my non-OBDII vehicles:

  9. ALS

    ALS Super Moderator Staff Member

    Pa. they test the gas cap for leaks and plug into the OBDII port, if there are no codes you pass.
  10. MaxxMPG

    MaxxMPG Hasta Lavista AAA-Vee Von't Be Bach

    In northeast PA, they test the gas cap and do a visual inspection to confirm that the catalyst is in place in the exhaust system and that all the various sensors/valves/etc are in place.

    In the NYC area, an OBDii car gets the scanner plugged in and if no tests are pending (recent reset of the light) and no codes are stored, it passes. On older cars, they are strapped onto a treadmill in the shop, with the drive wheels on rollers. A mechanic "drives" the car - at virtual speeds up to 60mph, with the sniffer wand jammed up the tailpipe (of the car, not the mechanic). CO, CO2, NOx and HC are all measured and reported. Cars older than 1981 are exempt from the test.
  11. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Super Moderator Staff Member

    In Maine only Cumberland County (which contains Portland) has an emissions test. It's gas cap pressure for 1974 or newer vehicles and OBDII check for 1996 and newer.
  12. SentraSE-R

    SentraSE-R Pishtaco

    In CA the smog check station checked the emissions system hoses, etc. visually. They also checked the OBDII for MIL history and monitor readiness flags. Lastly, they did the complete faux drive, tailpipe sniffer emissions test.
  13. Unleaded

    Unleaded Well-Known Member

    Here in Arizona they only check to see if the CEL works and if there are any pending or stored codes. That is if you have a car with an OBD II port. They will also check the gas cap. Other cars are tested through the tailpipe.

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