fault code p1123

Discussion in 'General Motoring' started by mk.kemkd, Jun 12, 2008.

  1. mk.kemkd

    mk.kemkd Guest

    I have hyundai accent 1.5 model 2000

    127000 mile

    I was had fault code p0422 and when try to remove (oxygen sensor)
    can't remove it I cut the electrical wire to remove it but I can't

    after that I have (p0135)

    I get (DW40) and I remove (oxygen sensor) and replace it by new one
    and remove the battery the (check lamp) was closed

    after 40 miles (check lamp ) opened
    and have this code (P1123) I was change all Spark plugs NGK, and Spark
    Plug Wires , and remove battery

    after some miles (check lamp) opened

    I remove (maf) and cleaned it and return it

    what can I do again for resolve this fault code
    mk.kemkd, Jun 12, 2008
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  2. mk.kemkd

    hyundaitech Guest

    P0422 indicates a problem with catalyst inefficiency. You probably need
    new catalytic converter. This code will eventually return.

    P1123 indicates a rich condition. Considering this occurred immediatel
    after replacing the oxygen sensor, I'd suspect the oxygen sensor yo
    installed is defective or isn't compatible with the vehicle. I'
    recommend using a factory oxygen sensor
    hyundaitech, Jun 12, 2008
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  3. mk.kemkd

    mk.kemkd Guest

    the oxygen sensor is (factory oxygen sensor) same a old one.
    and the technician off (scan tool) tell me, the oxygen sensor work
    good coze he read this in his scan tool.

    and this code P1123 was found after 4 day from change (oxygen sensor)

    and need to ask some thing
    I have program for scan can I see the problem code, by cable between
    my computer and car without interface or if u have scheme for easy
    interface i hope to send to me for scan my fault code with my self

    thank you

    like this photo

    prisediag7.jpg picture by kemks

    mk.kemkd, Jun 14, 2008
  4. mk.kemkd

    hyundaitech Guest

    When it comes down to it, there are many things that can cause P1123, bu
    there's a reason I think the problem is with the replacement oxyge
    sensor. Here's my logic:

    1. P0422 will not set unless the ECM thinks the oxygen sensors ar
    working correctly. This is because the ECM uses data from the oxyge
    sensors to determine catalyst efficiency. Hence, it's reasonably t
    assume the oxygen sensor was working properly prior to replacement.

    2. P1123 did not set until after the oxygen sensor was replaced. Sinc
    nothing had been done between the original P0422 and the subsequent P1123
    it's reasonable to assume there's some problem with the new oxygen sensor.
    If it is indeed a factory part (purchased at Hyundai dealer), then it'
    possible it's defective (not likely) or was damaged on installation.

    Other things that can cause P1123:
    -- stuck open purge control valve
    -- excessive fuel pressure
    -- air intake restriction
    -- defective air flow sensor.

    I don't currently have access to the photobucket site, so I cannot see th
    picture, but I don't have experience with any of the generic scan tools fo
    home use. About the only thing I can do is refer you to your owner'
    manual for the product.

    Also, if you can tell me what the mechanic saw that led him to believe th
    new oxygen sensor was functioning properly, that may assist me
    hyundaitech, Jun 14, 2008
  5. I started getting P0422's less than a month after I passed a smog
    check, so I'm assuming the downstream O2 sensor is bad (the upstream
    one went bad last year). Is that a reasonable assumption?
    Matthew Fedder, Jun 14, 2008
  6. mk.kemkd

    hyundaitech Guest

    Nope. You probably need a new converter. You should, of course, verif
    the oxygen sensors are properly connected (upstream to upstream connecto
    and downstream to downstream connector) and are displaying normal patter
    (other than a large amplitude from the rear sensor). But ultimately, at
    probability of 95% or better, the converter isn't working so well
    hyundaitech, Jun 14, 2008
  7. mk.kemkd

    mk.kemkd Guest

    the mechanic was tell me he test it my scan tool for measure it and he
    must between (0:1) if it that O2S will be good and this also in the
    autodata program ((O2 level at idle speed -------- Vol. % O2
    0,1-0,5 )
    and i was went to hem to assure this rate is my o2 rate and he was
    tell me your O2 is good.

    and I was went to hem to assure this rate is my o2 rate and he was
    tell me your O2 is good and he have this volume rate.

    the mechanic tell me may be (MAF) must replace it
    but this is so expensive to me, and I afraid when I change it this
    code return back

    * my fuel consumption is so high.
    * I was clean this MAF by (CRC).
    mk.kemkd, Jun 15, 2008
  8. mk.kemkd

    hyundaitech Guest

    O2 voltages between 0 and 1 are normal, but they don't necessarily impl
    the sensor is functioning properly. The ECM has the capability o
    adapting to skewed readings from a faulty or improper sensor, causing th
    voltage readings you describe.

    I'd also be interested in your short term and long term fuel trim values
    both in the current data stream and in the freeze frame data.

    It's possible you damaged the MAF by attempting to clean it, but since th
    same code was present before and after the cleaning, that's not likely. I
    too, doubt the MAF will solve your problem, but I don't have the car i
    front of me to diagnose, either
    hyundaitech, Jun 15, 2008
  9. mk.kemkd

    mk.kemkd Guest

    thanks for your attention, but if you can tell me some thing to assure
    if my O2S work good or not work or MAF work or not work

    coze until now I spend more money for resolved this problem

    and the new O2S was had same code from the old one , and this O2S was
    closed in the factory case and I think the factory made quality test
    before sell it , this make me suspicion of my O2S is defective if you
    have procedure for calibration it, please tell me how that.

    and when I replaced it with the new , try to be punctual and careful
    to not transact hard

    and thanks for your cooperation
    mk.kemkd, Jun 15, 2008
  10. mk.kemkd

    hyundaitech Guest

    "had same code"

    What is this code? I'm not sure you understand what I mean by "factory."
    Factory means a part obtained through the vehicle manufacturer's (Hyunda
    in this case) distribution network (in the U.S., that would be a Hyunda
    dealer) and in the vehicle manufacturer's packaging.

    For checking the air flow sensor, you'll be interested in technica
    service bulletin 01-36-022. You can view it at www.hmaservice.com-
    you'll need to register for an account if you don't have one. It give
    specifications for normal air flow readings. This TSB was intended fo
    diagnosing a P1128 code, so instead of MAF readings that are too low
    you'll be looking for MAF readings that may be too high.

    Unfortunately, there's little good way to test an oxygen sensor in th
    field. Checking for normal fluctuation between 0 and 1 Volt (a certai
    number of high and low switches in a certain period of time) is the best
    mechanic can typically do. But as I said previously, meeting thes
    criteria doesn't mean the sensor is good. Beyond that, the only othe
    option we'd have without some sort of sensor-testing apparatus would be t
    replace the sensor with one known to work properly
    hyundaitech, Jun 16, 2008
  11. mk.kemkd

    mk.kemkd Guest

    thanks for your replay i will tray to test another O2 one
    mk.kemkd, Jun 17, 2008
  12. mk.kemkd

    mk.kemkd Guest

    I was found the flex pipe is broken, are this reason for this fault
    mk.kemkd, Jun 21, 2008
  13. mk.kemkd

    hyundaitech Guest

    Could be. Start by fixing the pipe. Too much fresh air in the exhaust ca
    confuse the oxygen sensors
    hyundaitech, Jun 23, 2008
  14. mk.kemkd

    mk.kemkd Guest

    first I try to scan the fault code with another mechanic.
    the first mechanic found P1123 but another one, he found in the (X431
    scan tool)


    I was replaced flex pipe and ensure no have any leaking

    and don't clear the fault code when I drive by my car after many
    miles, I found my (check lamp) is close with it self

    but when refill fuel (92) I found the check lamp return open
    mk.kemkd, Jul 2, 2008
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