smog check and "check engine soon" light

Discussion in 'General Motoring' started by Mephistopheles Jones, Sep 3, 2003.

  1. Hey Everyone, my '93 SL2 just failed a smog check today (Los Angeles).
    Why? The "Check Engine Soon" light came on while the tester was revving
    the engine. He said this means I failed the "System Malfunction Light"
    test on the sheet (passed everything else). Is this accurate? I'm just
    used to ignoring the light, since it doesn't seem to indicate anything
    except that I'm driving faster than 60 mph. By the way, what does the
    "Check Engine Soon" light have to do with emmisions? Or does it indicate
    that something *might* be wrong with the emissions? By the way, I get a
    free re-test. Thanks!

    Mephistopheles Jones, Sep 3, 2003
  2. Mephistopheles Jones

    Bob Shuman Guest

    Mine came on when the EGR valve was malfunctioning. Simple fix was to
    remove the EGR (5 minutes job) and clean all the carbon deposits out (10
    Minutes), lubricate and reinstall. Pretty simple. I believe that the OBD
    code was 032, although this may not be correct since it is from memory.

    Bob Shuman, Sep 4, 2003
  3. Ahh yes, my car failed the test two years ago, and the mechanic cleaned
    something and it retested fine. I need to check the paperwork to see if
    it was the EGR valve, which sounds kinda familiar. Thanks man!

    So... I have ten days to do the free retest. If you were I, would you
    just clean the EGR valve, roll the dice and get the retest, or would you
    pay to have a mechanic look at it before the retest? Or are there
    places in Los Angeles that will run the codes for a reasonable price?

    My spark plugs are new, but the wires are old, so maybe I should just
    replace these like Jonnie mentioned.

    Thanks again, guys!

    Mephistopheles Jones, Sep 4, 2003
  4. Mephistopheles Jones

    Guest Guest

    What is the code causing the "Check Engine Soon" light to come on?
    Some parts stores will check the code for free.
    Knowing the code should help fix it.
    Guest, Sep 4, 2003
  5. Mephistopheles Jones

    Bob Shuman Guest

    The EGR gasket cost $3 and the part is easily accessible. There are only
    two bolts and an electrical plug to remove. The hardest part of the job was
    scraping off the old gasket (I used a rotary wire brush on a battery powered
    drill). I used a small screwdriver to scrape inside the valve body and
    there was a considerable amount of carbon that came out. The whole job took
    about 20 minutes max. What do you have to lose?

    Bob Shuman, Sep 4, 2003
  6. Still 900 times more than the paperclip that worked before OBDII.
    Joy. How do you even KNOW it's gone through a 'cycle'?
    This begs the question - if ODBII is that useful (and I doubt it is),
    why even BOTHER with the treadmill testing? If the treadmill testing
    reflects actual driving, why bother checking the ODBII light?

    CT dumped their testing program after enough people complained about the
    process (going to the state contracted center, waiting 45 min on line,
    paying a lot, possibly failing, finding a specially licensed mechanic,
    getting the repairs, repeating...), and about their cars getting trashed
    (which the state/contractor/EPA somehow thinks is the owner's fault,
    naturally), and about the general system.

    Could be worse, the drive by type sensors advocated in some circles are
    uselessly inaccurate, even according to the manufacturer's own data.

    NJ just implemented a new rule - 5 years between tests on any car made
    after 2000. NY still insists you get a test every freaking year. The
    sad thing being, there's not much proof this stuff works, it's just that
    states do it because the EPA basically blackmails them into it.
    Philip Nasadowski, Sep 5, 2003
  7. They're going for $100 on Ebay, so I can see myself buying one and selling
    it on Ebay when I'm done. I don't know anything about this stuff, but
    when I did a Google search, it said OBDII was for cars from 1996 onward.
    My car is a 1993 SL2. Does this mean I can read the codes without any
    special tools? If so, could someone describe how? Haven't found it in
    the Chilton or Haynes manuals.

    What is "I/M 250"?

    Actually according to the test, my nitric oxide level at 15 mph is
    borderline (703 measured, 720 max, but 150 is average) so I will take
    measures to get this down, since this is what I think the test should be
    about-- not some stupid light coming on. However, I got a reading of 335
    at 25 mph (avergae 136, max 774) so it seems the margin of error for the
    testing equipment may be ridiculously high, unfortunately.

    Interesting story: my sister got a new Accord last year, and the "check
    engine" light always came on in her car. Solution? The dealer told her
    how to disable it. Fortunately new cars don't have to take smog tests (and
    she isn't in a smog test state) :)
    So, the all the triggered problem codes are stored in the computer until
    you read them? I didn't understand this before.

    I called the DMV today, and they give financial aid to broke people who
    have to get repairs to pass a smog check, up to $500. I'm broke enough to
    qualify, but since they tell you where to get your car fixed, and the
    mechanic knows how much they're willing to reimburse, I'd be surprised if
    my "repairs" cost less than $500. They also let you get a temporary
    registration if the deadline passes and you still haven't passed the smog

    The tester took my gas cap off and inspected it, and this is part of the
    test. It's kind of depressing that your car has to be in tip top shape
    every two years, given that having a car here is essentially a
    requirement, along with liability insurance and $2.20 per gallon gas.
    Those who want seriously better public transportation here are dismissed
    as pinko commies.

    Thanks for all the help, and reading my rants!

    Mephistopheles Jones, Sep 5, 2003
  8. Mephistopheles Jones

    Bob Shuman Guest

    To your comment and question, the great state of Illinois, where I live, no
    longer does the treadmill testing if the vehicle is equipped with OBDII and
    the vehicle's computer shows it is in good running condition. The only test
    they do is to connect the OBDII cable and toggle the SES light to make sure
    it was not disabled by the owner (as you had suggested).

    On older vehicles, they still connect the computer and do the full
    dynamometer test.

    Bob Shuman, Sep 5, 2003
  9. Yes! the code is 32. I just went to AutoZone. My car is not an OBDII. I
    bought a thingy that is essentially a glorified jumper, for $2, and they
    showed me how to use it (Isn't that AWESOME!!!! Just $2 to read the
    codes!!!). They even showed me the page in my Haynes manual where the
    codes are! You stick the jumper in, and the "check engine soon" light flashes
    repeatedly to indicate the tens and ones digits of the codes. Cool as
    hell. Anyway, I got codes 26 (Quad driver output fault) and 32 (EGR
    system fault). Now I'm definitely not taking this to a mechanic.

    Thanks all!

    Mephistopheles Jones, Sep 5, 2003
  10. I know that some areas, when testing OBD II vehicles, will hook up a scanner
    and check the readiness flags for the various diagnostics that need special
    conditions in order to run (catalyst monitor, evaporative system, etc.) If
    any of them show up as "not ready", indicating the test hasn't been run
    since the system was reset, they tell the owner to bring it back later for a
    test after it has been driven for a while and the test has had a chance to
    run. This prevents people who have the Check Engine light on all the time
    from just clearing the code and immediately going for an inspection before
    it has a chance to run the diagnostic and turn the light back on.

    Apparently the NCVECS folks ( have found, from the
    vehicles that people have brought in to them to fix as part of the research
    they do, that it's rare for OBD II vehicles to have high emissions but not
    have the Check Engine light on. Therefore, it would seem that dispensing
    with the tailpipe test for OBD II vehicles would be a sensible thing to do
    Robert Hancock, Sep 6, 2003
  11. Have fun convincing the EPA of that. I/M 240 at least makes it look
    like something's being done, even though the value of it is suspect.
    not to mention, most mechanics around here hate the machines - they're
    unreliable, very expensive, and dangerous - one locked up at a shop near
    me and sent the car through a wall. The EPA will tell you that this
    stuff is safe, but anyone could tell you that sticking a car on a dyno
    is at best a risky proceedure...
    Philip Nasadowski, Sep 6, 2003
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