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Tin whiskers in accelerator pedal mechanisms -> MIL or drivability problems

Discussion in 'Off Topic' started by cwerdna, Oct 16, 2013.

  1. cwerdna

    cwerdna Active Member

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    Related to Another NHSTA Unintended Acceleration Complaint...

    Tin whiskers in accelerator pedal mechanisms have apparently caused problems for those w/Gen 1 (01-03) Priuses aka NHW11 and Camrys, in the past.

    See Accelerator Rebuild - lessons learned | PriusChat. Especially interesting were slides 8 and 13 of http://web.archive.org/web/20130601050821/http://nepp.nasa.gov/whisker/reference/tech_papers/2011-NASA-GSFC-whisker-failure-app-sensor.pdf.

    From slide 8:
    From slide 13:
    On the Gen 2 Prius (NHW20, aka 04-09 model year), AFAIK, their going to Hall effect sensors eliminated the issue w/the NHW11.
     
  2. NigelM

    NigelM Recovering Member

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    Umm, this is the TESLA Motors Club not the TOYOTA Motors Club......
     
  3. cwerdna

    cwerdna Active Member

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    TMC = Toyota Motor Corporation.

    But seriously, I started this just as an FYI about other possible malfunctions and failures mechanisms involving throttle by wire. This is yet another possible issue besides firmware bugs, alpha particles, electrical "gremlins", etc.
     
  4. doug

    doug Administrator / Head Moderator

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    Yeah, I think it's fine.
     
  5. Doug_G

    Doug_G Lead Moderator

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    Tin whiskers is a widespread problem caused by using no-lead solder (RoHS - Reduction of Hazardous Materials has been imposed on the electronics industry by EU and I believe also by California). The problem is that under certain conditions if the solder joint has some "stress" it will literally grow whiskers of tin that can short out to nearby circuits.

    In this case it doesn't sound like the car was really dangerous; rather it was not drivable. I've experienced a similar drivability problem with a gas car where there was a problem with the intake manifold - car speed was all over the map. Very annoying to say the least but there was no problem controlling the car.
     

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