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ELM327 Bluetooth put my car into Fail Safe Mode, how to fix?

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by RichPasco, Jan 12, 2016.

  1. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    I think I made a bad mistake and I need help to recover from it.

    I have a 2012 Plug-In Advanced Prius. I recently bought an inexpensive ELM327 Bluetooth adapter:


    It was connected to my car and via Bluetooth to my Samsung Galaxy Note 10.1 tablet. The car was at "Ready" in Park on EV battery power. Suddenly the ELM327 reported "UNABLE TO CONNECT" (to the car; the Bluetooth connection was fine). But worse, the car displayed: "CHECK HYBRID SYSTEM ... STOP THE VEHICLE IN A SAFE PLACE."

    Based on other posts here, I believe there is nothing wrong with the car, other than it entered Fail Safe Mode because of a problem with the cheap ELM327 adapter. For example:
    DTC U0073 Control Module Communication BUS Off | PriusChat

    But what do I do now? I have removed the ELM327 but the Fail Safe Mode persists. Having it towed to my nearest dealer (15 miles away) for them to reset it is an unpleasantly expensive option.
     
  2. bisco

    bisco cookie crumbler

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    try disconnecting the 12 volt for a few minutes.
     
  3. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    Are you certain that will do it? Or just guessing? I don't want to do all the work of taking up the trunk floor to disconnect a battery cable, and to lose all of my custom settings throughout the vehicle, just to test your guesswork.
     
    #3 RichPasco, Jan 12, 2016
    Last edited: Jan 12, 2016
  4. xpcman

    xpcman Senior Member

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    Try turning the car on and off 3 or 4 times. Often the check hybrid system message will reset itself after a few cycles.
     
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  5. bisco

    bisco cookie crumbler

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    guessing.:oops:
     
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  6. Tracksyde

    Tracksyde Member

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    It has happened to me (and others here). Just unplug it and like xpcman said, turn your car on and off a few times and it'll go away. IIRC, mine didnt go away until I actually drove it around though.
     
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  7. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    Well, that did seem to clear the Fail Safe Mode (all warning lights on) but not the "/!\ Check Hybrid System".
     
    #7 RichPasco, Jan 12, 2016
    Last edited: Jan 12, 2016
  8. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    Driving it around seems to be the key. I did unplug the AC power charging cable before turning the car off and on a few times. That took it out of Fail Safe Mode (all warning lights on) but it still said "/!\ Check Hybrid System" until I actually put it in gear, backed it out of my driveway and came back in.

    As it turned out, it was not necessary to disconnect the 12 volt supply.
     
    #8 RichPasco, Jan 12, 2016
    Last edited: Jan 12, 2016
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  9. mrbigh

    mrbigh Prius Absolutum Dominium

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    dito
    it has been a common problem with the cheap ODB adapters
     
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  10. Rebound

    Rebound Senior Member

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    Drats! Now we'll never know if that would have fixed it.
     
  11. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    It probably would have fixed it, but disconnecting the 12v battery also has other unwanted side effects.
     
  12. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    I finally got around to posting a review on Amazon.com
     
  13. RobH

    RobH Senior Member

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    I think ELM devices have a "hunt for protocol" mode. If that were invoked, who knows what misinterpretation could occur (well, I guess you have an idea...). So there are two issues - what mode does your (clone) ELM device default to, and what mode did the software you ran on it set it to.

    Could be the software you ran - the ELM could be perfectly OK.
     
  14. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    The software was a simple text terminal (chat window). I can look up the name if you want.
     
  15. RobH

    RobH Senior Member

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    The important thing is what commands were issued. I don't suppose you'd like to try them again...
     
  16. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    No, I am not willing to try them again, but I kept a log the first time:

    ELM327 v1.5
    >> AT Z
    ELM327 v1.5
    >> AT I
    ELM327 v1.5
    >> AT RV
    14.6V
    >> AT SH 7C0
    ?
    >> AT Z
    ELM327 v1.5
    >> AT SH 7c0
    ?
    >> AT @1
    OBDII to RS232 Interpreter
    >> AT @2
    ?
    >> AT Z
    ELM327 v1.5
    >> 07C021AC
    UNABLE TO CONNECT
    >> AT Z
    ELM327 v1.5
    >> 07C021AC
    UNABLE TO CONNECT
    >> AT Z
    ELM327 v1.5
    >

     
  17. bfd

    bfd Plug-In Perpetuator

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    Toyotas run power - through the OBD-II port. I don't know if that's common, but sometimes these dongles interrupt that power, and the system throws a fault as a result. The only way to circumvent this is to get a dongle that doesn't tap the plugs that deliver electricity. Someone with more knowledge about each pin in the OBD-II can probably provide more information. For me, the fix was to contact the mfgr (ScanGauge). They were aware of the issue and sent a re configured connecting wire. I was lucky that ScanGauge dealt with this enough times to know what the problem was and how to resolve it.
     
    #17 bfd, Apr 7, 2016
    Last edited: Apr 7, 2016
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  18. RobH

    RobH Senior Member

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    Several observations on the dialog...

    The version code of 1.5 indicates that the device is not a product of the ELM Electronics. They have never produced a 1.5 or 1.4a version. It is a clone. True ELM versions include 1.4, 1.4b, 2.0, and 2.1.

    The fact that the "AT SH 7C0" command was rejected with a "?" indicates that the active protocol is not 11 bit CAN.

    The protocol should probably be 6, ISO 15765-4 CAN (11 bit ID, 500 kbaud). It could actually be 0 (scan for protocol), or any other of the 12 supported protocols. ELM devices remember the last protocol used, and start up in that mode.

    The dialog should include a "AT SP 6" before the "AT SH 7C0".
     
  19. RichPasco

    RichPasco Richard C. Pasco, Ph.D.

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    That alone is enough to convince me that the Amazon ad was false, since it claimed "Latest Version V2.1 Super MINI ELM327" I want nothing more to do with this piece of junk.