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Help: strange warning light combo: dangerous?

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Prance_priv, May 5, 2020.

  1. Prance_priv

    Prance_priv Junior Member

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    2012 Prius V 70k miles

    Help! The following warning lights all came on immediately after turning on the adaptive cruise control (see attached photo)l:

    Slip Indicator light
    Dynamic radar cruise control
    Brake System Warning Light
    Malfunction Indicator Lamp (Engine Check)
    Hybrid System Warning Light
    Pre-Collision System Warning Light
    E3 displayed in the dash (see photo)

    Is it safe to drive? What might explain the combination of lights? A defective speed/cruise control sensor seems like a good guess, meaning if I DO NOT depend on the adaptive cruise control -- it is safe to drive?

    I tried cleaning the adaptive sensor (behind the Toyota symbol on the front grille?) but it had no effect.

    Any hypotheses or trouble-shooting suggestions?

    Can't find any thread(s) with similar problem.

    Thanks very much!

    Dan
     

    Attached Files:

  2. rjparker

    rjparker Tu Humilde Sirviente

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    Does it drive properly?

    If not, what is not acting right?

    The hybrid and brake lights are the most concerning and worth a proper scan. You could have them reset and see what comes back. Serious hybrid problems won't let it drive properly if at all. Especially if its inverter based. Serious brake problems usually means the brake actuator and booster assembly, a known issue with these models. But it will drive.

    The brake problems can throw the hybrid lights as well as the brake actuator is part of the hybrid regen process.

    While many would blame the 12v or at least suggest replace the 12v battery, I don't subscribe to that theory if it drives. Obviously if its the original 12v battery, its time, just as one might replace eight year old tires if they were original. On these cars, scanning with a very good code reader is usually the first order of business.
     
  3. Prance_priv

    Prance_priv Junior Member

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    It drives fine, I don’t notice anything. As I said, the lights all lit up when I turned on the adaptive cruise control, while driving on the highway. I haven’t tried to see if the cruise control works and I haven’t driven the car since I experienced these lights except to continue on the highway for about 5 miles until I was home, without incident.

    I don’t have access to a code reader, unfortunately. If it’s not urgent, I’d prefer to deal with it after things are a little bit more relaxed. Any comments or suggestions are appreciated.
     
  4. bisco

    bisco cookie crumbler

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    maybe a low 12v, have you been driving much?
     
  5. ChapmanF

    ChapmanF Senior Member

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    I would just skip the tea leaves and read the trouble codes. The lights mostly light up to let you know that there are codes to be read. Trying to glean more from patterns of which lights come on is a long run for a short slide, because the different computers in the car talk with each other too much, and will put up lights of their own because of problems they heard about elsewhere.

    That will all sort itself out when you have read the actual codes. You'll find there are codes described in the manual that literally just mean the computer reporting the code is telling you it heard about another code from another computer.
     
  6. rjparker

    rjparker Tu Humilde Sirviente

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    You might try disconnecting the 12v battery for a few minutes to attempt a code reset and see what comes back. If you wait until things are relaxed again it could be next year. I would do something rather than run around with hybrid and brake codes. They can be major concerns.
     
  7. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Do you have anything plugged in steadily to the OBD port. That was apparent cause of somewhat similar problem with our 2010.
     
  8. Prance_priv

    Prance_priv Junior Member

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    I have nothing plugged into the OBD port and I have not been driving much. No low batter light appears. I will attempt to disconnect the batter under the hood for some time and reconnect. Thanks for the suggestion.
     
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  9. bisco

    bisco cookie crumbler

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    you have a battery under the hood?

    not driving = low 12v
     
  10. Prance_priv

    Prance_priv Junior Member

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    Of course no battery under the hood!

    Can I pull a fuse on the 2012 Prius V to have the same effect as disconnecting the battery for a few minutes (to hopefully clear the codes)?

    Also, why would a low battery cause all of those lights to go on? And how long must one drive to charge the battery sufficiently? (I’m guessing it depends on the battery so an approximation please). I had driven about 10 miles after a few weeks of sitting idle and I had put on the adaptive cruise control right before the lights lit up.

    Also, can I connect a trickle charger to the jump-starting terminal in the fuse block or do I need to connect it directly to the 12V battery?

    thank you.
     
    #10 Prance_priv, May 7, 2020
    Last edited: May 7, 2020
  11. sam spade 2

    sam spade 2 Senior Member

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    If you are going to buy a charger, it should be a "tender" type automatic one......NOT a dumb trickle charger.
    The difference is important.

    The 12 V system runs the computer boards in the car.
    If that power supply is low, all kinds of strange things can happen.

    The onboard charging system is designed to keep the battery charged; not necessarily to REcharge it if completely dead. It might take many hours over several days to fully charge it.

    Unless there is a bad connection on a main cable, the jump points are fine for most battery operations.

    Hopefully the codes will clear themselves......IF the battery really is the cause.
     
  12. The Electric Me

    The Electric Me Go Speed Go!

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    The often told story around the Prius Chat campfire is that a low or failing 12 volt battery, morphs into a gremlin that can cause any number of codes, etc. The 12 volt boots up the computers.
    So often when someone reports a mysterious appearance of codes, check your 12 volt is an early refrain.
    On a 2012? It's probably a good first step.
     
  13. Prance_priv

    Prance_priv Junior Member

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    OK, fully charged the 12v battery through the jump-starting terminal. Tested it with a Multimeter (12.4-V).

    No change. Disconnected negative battery cable in the back of the car and reconnected.

    The following changes:

    E3 no longer displayed in the dash
    Dynamic radar cruise control and Slip Indicator light both gone

    But the following remain:

    Brake System Warning Light
    Malfunction Indicator Lamp (Engine Check)
    Hybrid System Warning Light
    Pre-Collision System Warning Light

    Drove it for about a minute. Noticed it would not go into electric mode (I stayed under 25 MPH), gas engine stayed on the whole time, even when idling and after hitting P at the end. And the three switches, EV, PWR and ECO Modes were not responsive. Could this be because the Hybrid battery is low? Only 2 bars, so not that low. Might I need to reset the Hybrid system? I think I once came across a way of doing that. Otherwise I am running out of ideas.

    Other strangety is when I went to open the car, yesterday (while 12V battery charging) and then today (battery full), the keys would not work. Had to open with physical key. Yesterday I held the fob to the Ready switch to get the car to turn on. Today I just needed to manually open the door and then the fob worked.

    Any suggestions? Thank you.
     
  14. Ivan White

    Ivan White Junior Member

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    12.4 V is too low. Get a battery tender and charge the battery for 24 hours. If not up to 12.8 v or above after that, change the battery. If it were me, I'd charge the battery on the top-post terminals, not through the jump-starting terminals.
     
  15. Air_Boss

    Air_Boss Senior Member

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    I installed a battery tender pigtail from 12V into cargo compartment for just such occasion, since the v often goes a month between road trips. Pigtail also has a battery status LED.
     
  16. ChapmanF

    ChapmanF Senior Member

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    Read the trouble codes. At 12.4 volts they are not fake or caused by gremlins. They are your car trying to tell you about an issue. Read them.
     
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  17. sam spade 2

    sam spade 2 Senior Member

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    12.4 does NOT indicate a healthy battery, especially right after being charged.
    Before you do anything else, you NEED a new battery.
    This is assuming your meter is accurate, of course.
     
  18. sam spade 2

    sam spade 2 Senior Member

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    Maybe not. IF his 12.4 reading truly was with absolutely no load, then it might well fall a lot more during the "boot up" process when a load is applied.
     
  19. ChapmanF

    ChapmanF Senior Member

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    Not enough to invent 'gremlins' or continue playing games other than reading the codes his car is giving him.
     
  20. sam spade 2

    sam spade 2 Senior Member

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    You have absolutely, positively NO way to know that.
    And implying that it is a fact is NOT being responsible.