Airbag Light On and Horn Not Working

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by A.J, Dec 21, 2024 at 8:47 PM.

  1. A.J

    A.J Junior Member

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    My 2010 prius airbag light came up and the horn also doesn't work. Even with the remote key alarm. So i know it's not the spring.
    Also tested the Airbag cable continuity and can see it went end to end from the Airbag cable to the output port under the steering.
    Only Error under Airbag is the B1906 ECM A.

    Incase anyone has encountered this kind of issue before, kindly give suggestion at least for the horn.
     
    #1 A.J, Dec 21, 2024 at 8:47 PM
  2. ChapmanF

    ChapmanF Senior Member

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    Not sure where you got the description "ECM A" for that code. Looks like "open in front passenger side pretensioner squib circuit" to me.

    The spiral cable ("clock spring") behind the steering wheel is the only single cause you could have of an airbag code and a horn problem. But then your code would be about the driver airbag, not the passenger seat belt tensioner.

    As it is, it just looks like you happen to have both a problem with the passenger seat belt tensioner squib circuit, and a problem with the horn.
     
    #2 ChapmanF, Dec 21, 2024 at 8:55 PM
  3. A.J

    A.J Junior Member

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    I already checked the spiral, all flex connection goes end to end.
    Also, remember the remote key fob alarm does not sound the horn too.
     
    #3 A.J, Dec 21, 2024 at 9:20 PM
  4. ChapmanF

    ChapmanF Senior Member

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    Did you read what I wrote? The spiral cable is eliminated by your previous checks and by the fact that the problem is with the passenger seat belt retractor (that circuit doesn't go through the spiral cable).

    So, with the spiral cable eliminated, you don't have a single problem with two symptoms. You just have two problems, one with the passenger seat belt squib circuit, and a different one with the horn.
     
    #4 ChapmanF, Dec 21, 2024 at 10:05 PM
  5. A.J

    A.J Junior Member

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    You are right, it was two different issue entirely just coincidental. The Airbag warning was for Driver belt sensor i think, while one of the horn cable port with an iron clip got misplaced and was touching the chassis (ground). Don't know what it is, but apparently wasn't meant to touch the ground (more like - touching + thing). Moving it away from touching the chassis solved the issue of the horn.

    However, before i discovered the issue I already went ahead to lose my Spiral and fixed one of the flex line that cut thinking it was the horn, but apparently it only fixed my AC control buttons on the steering wheel that hasn't been working for quite a long time. But hey, it wasn't a waste of time afterall. Just learnt a spiral can be fixed with mere soldering device.

    Thanks for the help, really appreciate it

    2.jpg 1.jpg
     
    #5 A.J, Dec 22, 2024 at 6:14 PM
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  6. ChapmanF

    ChapmanF Senior Member

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    It's unlikely to be the belt sensor, and more likely to be the squib that detonates the seatbelt pretensioner. This is a small b*mb built into the belt retractor spool mechanism to jerk it back and pull you in the seat for a crash.

    The description I found for your code referred to the passenger side belt.

    People might be interested if you follow up after some time to report on how long that fix holds up.
     
    #6 ChapmanF, Dec 22, 2024 at 6:27 PM
  7. T1 Terry

    T1 Terry Active Member

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    Another fix for the horn not working is a sticker on the rear window
    "Horn not working, watch for finger"
    if you get a laugh more than half the battle is won ......

    T1 Terry
     
    #7 T1 Terry, Dec 23, 2024 at 1:20 AM
  8. A.J

    A.J Junior Member

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    Actually the Driver's belt jerk mechanism is not working, will get it fixed soon. I might not have gotten the error code correctly when i posted, hence why you interpreted it as Passenger side but will also check the Passenger side too if there is any issue. Thanks again
     
    #8 A.J, Dec 23, 2024 at 7:08 AM
  9. ChapmanF

    ChapmanF Senior Member

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    Keep in mind that it is hard to tell whether the pyrotechnic pretensioner is working or not, as it never does anything until a crash when the airbag controller ignites it, and then it only goes once. The retractor then has to be replaced. The retractor is sometimes physically deformed after the pretensioner has fired.

    Is it possible the car was once in a crash that fired that belt's pretensioner? That would explain the code, and could also have left the ratchet mechanism not working right, if the retractor got a bit deformed.
     
    #9 ChapmanF, Dec 23, 2024 at 2:26 PM
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