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Prius C Speedometer offset/error

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by ghwong, Apr 6, 2012.

  1. ghwong

    ghwong Junior Member

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    Anyone out there facing this problem?
    From GPS and OBDII, I found that the MFD/VFD in the dash is >10% off..
    Any idea what is the problem and how can we resolve?
    Checked with the service centre but they don't know anything about this..
     
    #1 ghwong, Apr 6, 2012
  2. F8L

    F8L Protecting Habitat & AG Lands

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    Are you asking if the speedometer is off (too fast)?

    If so then keep in mind that nearly all cars exhibit this error. It is by design due to national laws in most cases. The GenII and GenIII Prius also exhibit this error. The GenII reads 2mph too fast and the GenIII is 1.5-2mph too fast when compared to GPS and Scangauge.
     
    #2 F8L, Apr 6, 2012
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  3. KK6PD

    KK6PD _ . _ . / _ _ . _

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    I just go 70, it saves time!
    I get passed quite often!
     
    #3 KK6PD, Apr 6, 2012
  4. cwerdna

    cwerdna Senior Member

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    #4 cwerdna, Apr 6, 2012
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  5. ghwong

    ghwong Junior Member

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    Mine is about 10% faster..
    Will this lead to odometer reading higher mileage as well?
    My warranty is 100000km (5years), this means I have only 90000km warranty in actual, if the odometer is following the MFD..:(
     
    #5 ghwong, Apr 6, 2012
  6. F8L

    F8L Protecting Habitat & AG Lands

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    The odometer reads correctly as does the internal computer. The manufacture designs the speedometer to read high to avoid lawsuits with people speeding because of speedometer errors. If you hook up a Scanguage or other device that reads the car computer you will find it to agree with GPS data. :)
     
    #6 F8L, Apr 7, 2012
  7. cwerdna

    cwerdna Senior Member

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    It depends. The speedo inaccuracy is not necessarily the same amount or even direction as the odo inaccuracy. 10% error is a lot though...

    http://www.caranddriver.com/var/ezf...lication/1e1b33f85f31df61e4830f32f82a5a71.pdf accompanied the very old article at Speedometer Scandal! - Feature - Car and Driver.
     
    #7 cwerdna, Apr 7, 2012
  8. strongbad

    strongbad Member

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    A 10% speedometer error is a serious design flaw IMO. My car's speedometer is 100% accurate with new tires.
     
    #8 strongbad, Apr 7, 2012
  9. ghwong

    ghwong Junior Member

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    Went to SC and request them to check the speedometer offset issue and whack them as they didn't give a reasonable explanation on how then calibration the speedometer.
    Finally they agreed to do a check but I will verify it on my 2nd service..
     
    #9 ghwong, Apr 8, 2012
  10. hnx676

    hnx676 Junior Member

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    First of all, I am happy to get to know another fellow prius c owner in SG.. :)
    The local SC is really nothing to offer us.. They did not even have the correct grade of engine oil for prius c :mad: (did you check what they put in during your first service?) ...

    The speed display is confirmed to be about 10% off as compared to Scangauge2.. When is your next service? I have about 2500KM more to go before my next one is due... Do keep us posted :)
     
    #10 hnx676, Apr 8, 2012
  11. ghwong

    ghwong Junior Member

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    Bro.. I just clocked about 2k only.. after the first service I'd notice a degradation in FC, due to the wrong grade of engine oil..
    But after the coming 2nd service (no oil change), I will try to sort the thing out with the SC on the speedometer before highlight to them on the engine oil.. Anyway already prepare my own 0W-20 to be replaced after their service..
     
    #11 ghwong, Apr 8, 2012
  12. ken1784

    ken1784 SuperMID designer

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    Singapore and the US speedometer regulations are different.
    EU, Singapore, JP and others follow UN/ECE Regulation No.39.

    The Singapore's 10% error is within the regulation.

    Ken@Japan
     
    #12 ken1784, Apr 9, 2012
  13. fuzzy1

    fuzzy1 Senior Member

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    Use your GPS to check this too. As noted earlier, speedometer and odometer errors are not the same, and speedometer regulations are different in different markets. I haven't heard anything about non-U.S. odometer regulations, but U.S. civil law has placed expensive consequences on manufacturers for odometers that read even 2% too high.
     
    #13 fuzzy1, Apr 9, 2012
  14. hnx676

    hnx676 Junior Member

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    sorry for the off-topic discussion ...

    I presume you also have the 5 year service free from the dealer, right? Then why should you bring the 0W20? The oil should be included!! You should scold them badly and force them to bring in the right oil... This is what I did and this is what I will be doing during my next servicing...

    PS: What color is your ride, mine is Black :)
     
    #14 hnx676, Apr 9, 2012
  15. ghwong

    ghwong Junior Member

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    Yup.. have 5yrs free service, if not mistaken the 5k service has no oil change.. the 1k oil was already screwed up by them, that is why i gonna use my previous 0W-20 to replaced it if they not gonna change.. Had a very bad experience at the service centre, i already wrote feedback on how they treated customer like that..
    Mine ride is Lime Pearl White used to own a Black Honda Fit.. nightmare in maintaining black due to swirl mark...:(
     
    #15 ghwong, Apr 9, 2012
  16. hnx676

    hnx676 Junior Member

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    Same bad experience at SC and after wave of complains I still do not see any improvement... think we should get in touch to see this through together with the SC.. two voice together is always better then one..

    As for the swirl mark on black car, I have 2 black cars before this... and not much of a problem for me, probably because I do my own washing and grooming... Anyway, dig Lime Pearl White... Was considering this or grey if black mica was not available... Very unique color :)

    Anyway :focus:... The speed difference was not an issue to me until I install a speed activated auto door lock... That was suppose to lock at 20Km/h but only start to work on mine at 25Km/h... It sort of trouble me during installation as I wanna make sure it works..
     
    #16 hnx676, Apr 18, 2012
  17. Mr Incredible

    Mr Incredible Chance favors the prepared mind.

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    I put 14's on my CRX, which was set up for 13's. The correction factor was 1.06046. Six percent was 2.5-3 mph at 60 mph.

    The speed was corroborated by my GPS unit and a radar sign on the highway.

    My truck is spot on. My Camaro is spot on. Daughter's truck is spot on. I don't think it's all that common to have a vehicle off very much.

    That being said, I think the new C is maybe 1 mph off between the speedo and the radar sign. Too soon to have studied it very much.
     
    #17 Mr Incredible, Apr 19, 2012
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