1. Attachments are working again! Check out this thread for more details and to report any other bugs.

09 Prius - Red triangle issue

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by averageman97, May 12, 2020.

  1. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    I'm new here and hope this is an okay place to post this. My wife has an '09 Prius. The other day when she got in to drive the car, it would not start up. She called me and I came to check on it, there were a few lights on the dash including the red triangle. I noticed quickly that the lights were all very dim (it was dark outside so it was easily noticeable) my first thought was the 12v battery. A little more investigation confirmed this and we went the next day and bought a new battery and installed it. We then got in to drive it again for a test drive to make sure everything was running smoothly. For a few miles everything seemed good but when we stopped at a red light and turned on the AC the triangle came back up. We pulled off the road and checked it out again but I couldn't find any apparent issues. We also turned the car off but when we turned it back on the dash lit up again with several lights and the car wouldn't go into any gear except neutral. I called her dad who is much more knowledgeable about cars than I am and he came to check it out too. He opened the trunk and messed with the battery cords a bit and that got rid of the light and allowed the car to start. However, as soon as we pulled out of the parking lot the light came back on. It was a short distance to our house so we just kept going with the red light on until we got home. When we got there we checked it out again and tried what he did with the battery but this time to no avail. Now, the red light is on constantly if the car is on as well as several other dash lights. The shifter will not go anywhere except neutral and the "B" engine braking option is not even presented as an option on the screen to shift to. Any ideas on what this issue could be? Thanks!
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    welcome!

    check the 12v health, they don't always come with a proper charge. then get the trouble codes read.

    it could be your hybrid battery, how many miles on her?
     
  3. 05PreeUs

    05PreeUs Senior Member

    Joined:
    Oct 1, 2016
    1,097
    563
    0
    Location:
    MSP
    Vehicle:
    2005 Prius
    Model:
    N/A
    One of the things that many folks do not realize is that the 12v battery has nothing to do with "starting" the Prius. All the 12v battery does, and it is SMALL for a "car", is to power up the electronics in the car. The Hybrid system (actually MG1) starts the engine.

    So, the car can "start" with a nearly dead 12v battery, yet still have all sorts of warning lamps and low voltage problems, due to the low voltage.

    If that is the case, fixing the cause of the low voltage will resolve the lights, typically it is a bad battery and/or poor electrical connection. It is not DIY friendly to the uninitiated to determine if the battery, Hybrid system, fuse or wiring is the root cause, but doable.
     
  4. ttou68

    ttou68 Active Member

    Joined:
    Sep 9, 2017
    340
    197
    0
    Location:
    40509
    Vehicle:
    2010 Prius
    Model:
    III
    I'm assuming you bought a brand new 12V at the auto parts store, not a refurbished one.

    I would suggest take it to an auto parts store or maybe someone you know have an OBDII scanner to check for fault codes and also double check your new 12V battery voltage..


    Posted via the PriusChat mobile app.
     
  5. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    Thanks for the replies! I checked the battery voltage via the settings menu on the radio - accessing it by holding options and turning the headlights on and off 3 times - sorry, not sure exactly what that menu is called. And it seemed to be good. I think it was reading at 11.7V. I ordered a code scanner from Amazon which should be here in a couple on Saturday. I'll update you all when I get the scanner in and check the codes.
     
  6. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    about 170,000. Car has always ran pretty well. It's got some body damage from a couple accidents but the internals have always been pretty sound up till now.
     
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    it happens to the best of us as we age :cool:
     
  8. 05PreeUs

    05PreeUs Senior Member

    Joined:
    Oct 1, 2016
    1,097
    563
    0
    Location:
    MSP
    Vehicle:
    2005 Prius
    Model:
    N/A
    Nope, that is DEAD.
     
  9. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    Okay - sorry for the long wait, had a very busy week and didn't have much time to check on the car. First off - retested the battery tonight and it tested at a little over 14 volts which I understand is about standard. Red light was still on but no check engine. It let me put it in gear, I drove it about a mile or so and everything was well. Turned on A/C, radio, windshield wipers and headlights and still seemed good. Got back to the house and plugged in the code scanner, it brought up 2 codes but they were N/A 01 and N/A 02 which I understand to mean that it can't read the codes so not sure what that means. Anyway, I cleared the codes and the red light went away. Let it set for a few minutes and turned it off. Tried turning it back on, got red light and a slew of dash lights and it wouldn't allow me to pull it into any gear aside from neutral. Checked battery voltage and it was sitting at 10.8 that time. Turned it off again and let it set for several minutes, turned on again and everything came on fine, not even a red light and battery was back to reading at 14+. I have no earthly idea what it's problem is. Any ideas? I'm calling my mechanic tomorrow to see if I can bring it to him and let him see what he can find out.
     
    bisco likes this.
  10. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,448
    3,751
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    Your battery voltage is not 14+ volts, that reading is the DC/DC converter as you are in READY mode. Your 10.8 V is the tell. Replace the 12 V battery and at least that is one problem solved.
     
  11. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    Will check on that as well, thank you.
     
  12. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    Started car up today and it came on but with red triangle and several dash lights. Took it on a drive and noticed the hybrid battery is not charging at all. Does this always entail an issue with the hybrid batteries or can it be something else causing that?
     
  13. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    could be the inverter, but unusual
     
  14. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    107,571
    48,862
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    is this a car worth investing some money in, or time to move on?
     
  15. edthefox5

    edthefox5 Senior Member

    Joined:
    Jul 25, 2007
    10,096
    4,795
    0
    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    Bad hybrid battery
    Bad 12 volt battery too,
     
  16. averageman97

    averageman97 Junior Member

    Joined:
    May 1, 2020
    11
    2
    0
    Location:
    USA
    Vehicle:
    2020 Prius PHV
    Model:
    Upgrade
    That's what I was afraid of. It's not worth investing in. It's got some extensive body damage on the front after a couple accidents. They never damaged the internal parts but the body on the front is held together essentially with zip ties and prayers. I'm gonna take it to my mechanic this week to give me a final verdict but I'm afraid we'll be in the market for a new car soon.
     
    edthefox5 likes this.