What is Prius trying to tell me with all this beeping?

Discussion in 'Gen 3 Prius Main Forum' started by Johnny Cakes, Mar 10, 2017.

  1. Johnny Cakes

    Johnny Cakes Senior Member

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    After turning off the Prius, here are my symptoms -- what is Prius trying to tell me?

    1. Open door: constant beeping inside car begins. This beeping will continue until the door is closed.
    2. Get out, close door: three beeps outside car
    3. Remote for lock/unlock doors does not function; must use hard key to lock/unlock.

    THERE IS NO KEY IN CAR!!

    This happened once before and, after awhile, the behavior stopped and everything worked normally again, including the remote.

    Given these symptoms, what is a logical cause?

    Thanks!
     
  2. dorunron

    dorunron Senior Member

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    FWIW, based on the symptoms you reported it sounds like the Prius "thinks" it is NOT turned off.

    All three of the items you describe WILL happen if the Prius is still on when you get out.
     
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  3. drysider

    drysider Active Member

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    It seems unlikely with a 2015, but always check the 12v battery when weird things start happening.
     
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  4. Johnny Cakes

    Johnny Cakes Senior Member

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    Great lead and I think you have pretty much nailed it.

    The car is definitely OFF -- I get the MPG summary like usual when turning off the car.

    BUT....accessory seems to be on. I know that because I am getting 12v at the cigarette lighter. So the car is NOT in Ready mode, but IS in accessory mode.

    In the three months that I have owned this car, this has happened twice. It usually lasts for a few days and then, just as suddenly as it began, things are back to normal. I have not been able to determine any pattern to getting in/out of this state. I do use the cigarette lighter as a 12v source, so maybe that is somehow related.

    Any leads / suggestions / guesses on how did I get in this state and how do I get out of it?
     
  5. bisco

    bisco cookie crumbler

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    don't recall anyone reporting this before. any aftermarket equipment?
     
  6. dorunron

    dorunron Senior Member

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    After checking things in "accessory" mode, "OUR" Prius will do "ALL THREE THINGS" that is described above.

    Based on what is written in both of your posts, it "sounds" like you might be having a problem with either the power switch OR a ECU in the circuit. Either way, since the problem is sporadic it will be difficult to troubleshoot and repair.

    At this point it really is best guess as to what the proper fix would be. You could throw parts at it all day long and never fix the problem. I too question if there might be some sort of aftermarket device installed on the car.

    Bottom line is this. It is NOT normal for the Prius to enter "Accessory" mode (orange LED on power button) by pushing the power button ONCE when shutting down. Normally to enter "Accessory" mode one has to begin with the Prius being completely "OFF", then pressing the power button ONCE WITHOUT pressing on the brake pedal. Also the 12 volt outlet should be powered down when the Prius is OFF, however it will be hot when the accessory mode is in use.
     
    #6 dorunron, Mar 14, 2017
    Last edited: Mar 14, 2017
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  7. DonDNH

    DonDNH Senior Member

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    It is possible that you have a faulty power button that is causing the problem (acting like you've hit the button twice causing a power off and then enter accessory mode).

    But in case an ECU is causing the issue, try disconnecting the 12V for a minute or two in order to force a reboot and see if that clears the issue.
     
  8. jerrymildred

    jerrymildred Senior Member

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    I think I also suspect the power button. I would think that it would be made to not "bounce." If that's not working, a switch can see one press as several because when you press a momentary contact button, the contacts can sort of chatter back and forth for a tiny fraction of a second.
     
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  9. Johnny Cakes

    Johnny Cakes Senior Member

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    I appreciate your taking the time to make that test. It is a great data point, as it confirms that the car is behaving exactly as it should in accessory mode, lending support to the notion that that is what is going on.

    The former owner did have a remote start installed, so I guess that is a likely culprit since it involves the start.

    And thanks to those who suggested the start button itself. That's another possible culprit.

    The next time this happens, I am going to take a look at the start button to see whether it is glowing orange, as it does in accessory mode.

    I am also going to flip the "remote start kill" switch and see whether that makes any difference.

    Finally, I do run a significant amp load from the cigarette lighter, sometimes charging a LiPo battery. Perhaps that is back-feeding power somehow and "confusing" the car.

    I'll report back -- thanks again to all who have replied. I've only had the car/been in this forum for a couple months but I am impressed with the help here.
     
  10. jerrymildred

    jerrymildred Senior Member

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    Sounds like a good plan, Johnny.
     
  11. Mendel Leisk

    Mendel Leisk Cloud Watcher

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  12. mrwzrd

    mrwzrd Junior Member

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    My 2012 has been perfect until I wired a dash camera into the accessory power circuit. I've notice 2 things. 1- sometimes the camera does not shut off or come on when the car is started or shut down. 2- I have gotten the beeps as described above. Last night I shut down and waited for the camera to beep and shut down...it did not. Adapter was showing power. Car was off. Power button unlit. Got out of car....beeps.... got back in, went to aux then shut it off. Camera shut down.
    Today... had same thing happen at shutdown. unplugged camera. Camera shut off. Plugged in camera....did not start back up. Aux power now off.
    It's behaving like the power circuit is being held on by the camera.
    Have cycled the power a dozen times without the camera plugged it.... shuts down each time and no beeps when exiting.
    Have the car pulled in and the meters out.... probing time!
     
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  13. Johnny Cakes

    Johnny Cakes Senior Member

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    Yep, mrwzd, turns out that is exactly what is going on with my issue. Of the three causes I listed as suspects, this was the least likely but has been confirmed. Your post is a double confirmation. Please circle back and let us know what you find out with meter.

    Here's how I was able to confirm and perhaps another data point to figure out what is happening.

    Turn car off, with electrical load plugged into accessory outlet (cigarette lighter).
    Car beeps when door open.
    Unplug load, beeping immediately stops.
    Plug back in quickly (five seconds), beeping resumes.

    Unplug and wait long time, then plug back in with no beeping.

    So it is definitely related to a electrical load on the accessory outlet at shutdown.
     
  14. mrwzrd

    mrwzrd Junior Member

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    Update... meter says everything is "ok". Voltages are what they should be when on and off.

    That said.... I did find something.

    I was suspicious of the power button... so over a period of a week I made sure I was very deliberate in pressing the button. And I used what I would describe as a "long press". Even with the dash camera connected I did not have a single issue. I can not know if the button is needing replacing but maybe I'll price it out and see if it makes a difference. Meanwhile, I just "casually" press the power button.
     
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  15. Johnny Cakes

    Johnny Cakes Senior Member

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    I'll try deliberate pressing also next time this happens, although I once had this problem for about a week (load connected the whole time) and it seems like I would have at least once done a deliberate long press.

    Going rate on eBay for a start button (and assembly) is about $25 -- if you want to swap out to test, I'll pay half!!!

    Although I feel much more comfortable now that I can get the problem to stop by unplugging the load, and also by the fact that you experienced the problem also, it would be nice to get to the bottom of this.
     
  16. mrwzrd

    mrwzrd Junior Member

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    Have not changed the power button....but... I did swap the Pilot camera for a Garmin DashCam 55 and I have not had the problem. So... yesterday being a nice day... I sat in the car and swapped cameras back and forth. (Also borrowed 2 other cameras, another Pilot and the other just said Star on it. Owner says he paid $40.)

    Guess what? All of the cameras except the Garmin produced the problem.

    I'm going to go out on a limb and guess that the cheap cameras do not have a blocking diode in the power circuit and Garmin does. With the more deliberate press of the button it might be that we "step over" the glitch time frame. Regardless, I am not running the Garmin and not looking back. (BTW...The Dashcam 55 is really cool. In addition to full HD, you can talk to it. About a dozen times now I've told it to save a video segment because of something that happened and it has don't so. You can also tell it to take a picture which was really cool when we went on vacation... I had it take a picture of various milestones along the route and ended up with a photo album of the trip when I got home. (ok...enough unsolicited endorsement ..))
     
  17. BZzap!

    BZzap! Senior Member

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    I think you have hit the nail on the head with your theory about feedback from your accessory device. I think the battery in your device/ devices is the culprit. There are products that are designed to plug into your power outlet that keep the ECM alive when replacing your 12v battery. This is accomplished with a 9v battery and a pigtail that plugs into the power port. This might also be a sign that your 12v battery may be dropping below the designed voltage limits that are required to keep the ECM alive.
     
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