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NCT: OBD testing.. did they screw up my car?

  • 18-09-2021 10:57pm
    #1
    Registered Users Posts: 29 smartarsery


    My car went in for the NCT a few weeks ago and it had a check engine light on when it went in (for a minor communication issue with the TCM), and failed on it, but when it came out the check engine light was gone. It seems likely that they plugged into the car since they're now doing ODB testing, and my particular check engine light usually doesn't go away unless it's been cleared. It had been on for about 6 months before this and never went away by itself.

    So I went back yesterday to get a retest with the check engine light cleared, and it passed no problem, and I thought "great!".

    Then today the check engine light came back and so I plugged in my scanner and was quite surprised to see that it wasn't the same old error that I always got before U0001, but instead it was a "module configuration failure" error B2477. The error popped up in the "audio" module on the car but from what I've read it seems like it could be related to a number of things like wipers, power windows, central locking, etc, maybe anything on the LIN bus. But I think everything in the car is OK.

    So I'm kind of wondering what exactly they're doing in the NCT when they plug into the OBD port, and what software they're using?

    Does anybody know?

    I mean, are they using an ELM327 Bluetooth device?

    Or a Snap-On scanner?

    Or official manufacturer software for each model of car?

    Or some of their own custom NCT software?

    Getting unusual behaviour twice after two tests suggests that they aren't just reading the values and checking for errors, or maybe that's all they're doing but the software is interfering with some cars.

    Anybody else get weird behaviour after a recent NCT?



Comments

  • Registered Users Posts: 30,657 ✭✭✭✭ listermint


    Em... You've already said you've an issue with your TCM perhaps that the key issue here?



  • Registered Users Posts: 29 smartarsery


    To the best of my knowledge they're on different networks. The TCM, ABS, ECU, etc are all on the high speed CAN, while the radio, wipers, central locking, etc, are all on the slower LIN bus.

    And it's unlikely the TCM issue would lead to a module configuration issue in a different system, especially since I don't even have the TCM issue at the moment. Of course it could just be coincidence that both events happened after going for an NCT.



  • Registered Users Posts: 30,657 ✭✭✭✭ listermint


    I'm big fan of DIY but id say bring this one to a garage that has a reader related to your vehicle type . Rather than general OBD ELM types.



  • Registered Users Posts: 26,352 ✭✭✭✭ Dempo1


    I presume all the NCT test centres are doing is looking for any errors and not resetting anything. This said OP mentions a fail based on engine warning light showing, I've seen other posts suggesting this is not a fail issue so a little confused. (Perhaps it once wasn't a fail issue)

    I also read there's a period of introduction for this new aspect of the test procedure, some discretion, flexibility etc but I'm open to correction.

    Does anyone have an idea what this new aspect of the test will actually look for. I have an occasional warning light come on , mind of its on kinda of thing, my mechanic says its a known issue (Renault Clio Diesel) , as it happens its never on when NCT tests due, apparently its to do with resetting after servicing which I get done regularly.

    Would be interested if anyone has an understanding of what NCT look for in this new check, mine not due until December

    Thanks 😊

    Is maith an scáthán súil charad.




  • Registered Users Posts: 2,660 ✭✭✭ 9935452


    They are looking for faults with the brakes , the ABS and EBS. If they spot anything with these with the scan its an advisory pass but will be a fail next year..

    I cant seem to post a link for it



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  • Registered Users Posts: 26,352 ✭✭✭✭ Dempo1


    Thanks for that, I was just curious really because there's an endless amount of potential issues a scan could show, I guess my concern was those annoying errors that that don't really have an explanation. I'm certainly no mechanic, I'm lucky to have a genuinely brilliant one and I've had cars over the years with errors or light coming on for not apparent fault or reason.

    Thanks again 😏

    Is maith an scáthán súil charad.




  • Registered Users Posts: 29 smartarsery


    Yea, when I took my car in in April, it passed fine with the engine light on, but then in September it failed, guy said it's an automatic fail now, and they wouldn't even check the emissions with the check engine light on.

    Here's the NCT manual regarding OBD testing: nct-manual-june-2021.pdf (ncts.ie), besides ABS they also look for problems with emissions, and I'm sure they'll probably look for anything else they think might be "dangerous" or illegal, stuff like EGR blanking or rewriting the ECU to hide faults, change VIN etc. I think when they have the government behind them they can say that pretty much anything is dangerous if you want to, like a leaky sunroof could cause water to drop on to some wires and set the car on fire and burn a school bus full of kids, etc.



  • Registered Users Posts: 26,352 ✭✭✭✭ Dempo1


    Thanks for the link 😀, I'm sensing (no pun intended) more and more reasons to fail . I get genuine safety checks are of course critically important, just fear those like me that have had those unexplainable engine warning light issues will have difficulties in the future. An electric Bike, looking more and more appealing 😁

    Is maith an scáthán súil charad.




  • Registered Users Posts: 2,576 ✭✭✭ Montage of Feck


    The genuine petrol loving motorist is under unrelenting attack from every direction.



  • Registered Users Posts: 29 smartarsery


    Yea, it sucks.

    I think since an engine light is a fail nowadays, there'll be a hell of a lot of perfectly good cars going to the scrapyard because they have a minor fault that doesn't interfere with anything, but would cost thousands to fix.



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  • Registered Users Posts: 26,352 ✭✭✭✭ Dempo1


    Steady on now what about us Diesel loving motorists 😁

    Is maith an scáthán súil charad.




  • Registered Users Posts: 2,844 ✭✭✭ Dr_Colossus


    Not my experience, I had the NCT on my 07 Volvo S60 about 3 weeks ago and it failed on an Anti Skid Service Required notice on the dash which appeared the previous week. The NCT printout of OBD Faults was clear as the Anti Skid Service Required notice only shows on Volvo's Vida Dice software.

    I've since learned that I can reset the Anti Skid Service Required notice but it reappears following a hard left turn so it transpires that a segment of the SAS (Steering Angle Sensor) has gone bad.



  • Registered Users Posts: 29 smartarsery


    That's interesting, sounds like they're not using a totally generic scanner so then. It surely wouldn't be cheap to get separate software for every manufacturer for every NCT centre in the country. My guess would have been that they'd use a top of the range Snap-On or Autel or something like that.

    But it's rightly infuriating when you fail on something like traction control, when it's a feature that every car doesn't even have.



  • Registered Users Posts: 2,660 ✭✭✭ 9935452


    Tbh im only going by what their website is saying .

    Out of curiosity though ,is there a light in the dash indicating a fault.

    Afaik thats part of the abs system . A fault in the dash for the abs will fail you too. As per the nct manual

    I would take what they say with a pinch of salt too.

    I failed for a broken rear spring.

    They told me they couldnt test the suspension as the spring was broken.

    Even though the suspension test is before the visual check for the springs



  • Moderators, Politics Moderators Posts: 33,269 Mod ✭✭✭✭ Seth Brundle


    But it's rightly infuriating when you fail on something like traction control, when it's a feature that every car doesn't even have.

    The logic is that if your car has a feature, especially a safety feature, then it must work. Nothing infuriating about that!



  • Registered Users Posts: 29 smartarsery


    I'm sure there are plenty of arguments for and against it, but the bottom line is that if your car fails on an "extra" feature, and you get infuriated, then by definition it's infuriating!



  • Registered Users Posts: 4,703 ✭✭✭ SCOOP 64


    Well if i have a intermittent fault properly best to bring my scanner with me just in case and do a reset if your unlucky enough for it come on on the way to NCT.



  • Registered Users Posts: 29 smartarsery


    That's what I did the second time 'round for the NCT, brought the scanner with me just in case. The light came on again a week after the initial test, and didn't come back after I cleared it, but I was dreading that it would come on during the test, another €28 down the drain and try again!

    But I did manage to get rid of the new fault (mentioned in the OP) today by disconnecting the battery, and the sorted it when the scanner wouldn't, so it seems like either a random glitch, or else something that got screwed up during the NCT.



  • Registered Users Posts: 477 ✭✭ Speedline


    Disconnecting and reconnecting the battery will only turn the light off. It won't erase the code from the ecu. If the car is plugged in, the fault will show up.



  • Registered Users Posts: 29 smartarsery


    With normal fault codes, yes, but this error was from a "configuration" fault. And the error is also gone now so it has sorted it. At least for the moment anyway.

    Before I disconnected the battery the fault and the light would come back immediately after clearing the code, but now both are gone. Kind of seems like the car rechecked all the modules when I reconnected the battery and found that everything was actually OK. Obviously it would be different if it was a hard fault, like a broken wire or something.



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