OBDII U0129 and Failed Bluetooth Adapter

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Robert John, Jun 30, 2023.

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  1. Robert John

    Robert John Junior Member

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    I recently installed the latest version of Torque Pro on a new cell phone, and while driving my Gen 2, suddenly the Red Triangle of Death appeared. I pulled-over; opened Torque; got a U0129 code.
    Made it home; went on-line; read everything I could about U0129 (service manual not very helpful); got the impression that U0129 was potentially a catastrophic communication failure… and difficult to troubleshoot. Too early in the day to start drinking.
    While combing through this forum, I noticed a member's comment about a bad OBDII Bluetooth adapter: “I once bought a cheap OBDII Bluetooth adapter and ended up getting some very strange communication problems when I plugged it into my '07 Prius - seemed like the cheap unit hosed the comms bus. Unplugged it and everything went back to normal.”
    Sooo… before I put a ‘For Sale’ sign on the car (or worse, took it to the dealer), I removed the adapter and pushed the Power button: Red Triangle of Death still there. Dang! Powered-down, pushed the Power button again and… Red Triangle of Death gone!
    I’ve been using the same adapter for several years on my 2001 Vitara, and 2007 Prius (since buying it two years ago) - VERY helpful! But, it appears it may have come to the end of its useful life... or it has an issue with my new cell phone.
    Thanks again to everyone in this forum!
     
    #1 Robert John, Jun 30, 2023
  2. bisco

    bisco cookie crumbler

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    people have reported problems when leaving any reader connected, but it's inconsistent
     
    #2 bisco, Jun 30, 2023
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  3. dolj

    dolj Senior Member

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    More likely the cheap OBD adapter.
     
    #3 dolj, Jul 1, 2023
  4. ChapmanF

    ChapmanF Senior Member

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    As I remember it, there's lots of good information there.

    That sounds less helpful than what's in the manual.

    I built a gizmo once using a J1962 connector where they'd cheaped out on the plating of the pins. It had no problems at first, but after several years it would cause an immediate bunch of comm errors just by being plugged in. Rebuilt it using a connector with gold-plated pins and it was fine, could plug it in and out with the car on and never a glitch.
     
    #4 ChapmanF, Jul 1, 2023
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