Prius v: Multiple Warning Lights, Hybrid Battery Code, but 12v Disconnect Fixes it. Huh?!

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Merv Himself, May 9, 2020.

  1. Merv Himself

    Merv Himself Junior Member

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    Hi all. I'm trying to avoid a trip to the stealership. Any help would be much appreciated. Buckle-up for a long, detailed description...

    2013 Prius v
    160K miles
    Still consistently getting over 50MPH
    Brand new 12v battery
    Intermittent problem described below has been going on for about 4 months.

    PROBLEM: Upon startup, I am greeted with a fabulous array of 4 warning lights:

    slip indicator
    brake system
    check engine
    hybrid system warning

    (I have discovered different people sometimes use different names to describe these lights, so I am providing specific pictures to make sure we are all on the same page.)

    TRIED SIMPLE THINGS FIRST: Inspected the 12v battery and noticed a lot of corrosion on the negative terminal. Cleaned it up, put it back together, the lights went away and I was able to drive it for several days with no issues and optimal energy performance in excess of 50MPH.

    ISSUE RETURNED: After a few days, the issue returned. This time I let it run for a while and did the following:

    -Checked turbulence of the inverter coolant reservoir. It had slight turbulence, not a tsunami. But my understanding is that's quite normal for this model. No coolant movement whatsoever in engine coolant reservoir, but not really sure if there should be. So, motivated by hope & prayer beads, I disconnected neg. battery terminal, let it rest, reconnected it, and the car functioned like normal again.

    IMPORTANT POINT 1: When these errors light up, the ICE is idling continually. It never switches over to electric mode. Also, pushing the EV or ECO selector buttons on the center console has no effect. The car just continues to idle from the gas engine.

    IMPORTANT POINT 2: I realize disconnecting the battery is probably just clearing the error lights. However, if there is a problem with a coolant pump, the inverter, or even the hybrid battery itself, disconnecting then reconnecting the 12v battery should not suddenly cure that problem. And by monkeying around with that 12v battery as I've described, the car works as designed and even switches back over to electric mode like it's supposed to. And keep in mind, I've seen no drop in MPG.

    WHERE I AM TODAY: In a state of confusion & despair. A couple weeks ago, while hopped up on "Hopium", I installed a new 12V battey. The car worked like a champ for about a week and then the problem started again. The solution of disconnecting/reconnecting the 12v battery always cures it and power switches from the ICE to the HYBRID BATT just as it should.

    CODES: After my latest "reset", I finally did what I should have done months ago. Went to the Auto Store and used their code reader. It shows one bone-chilling code which is permanent and un-eraseable: P0A80 "Replace Hybrid Battery Pack". But let's think about this folks. If the hybrid battery was bad, do you really think I would be getting consistently great MPG? (I'm wondering if this is simply a default error code based on high mileage)

    WHAT I NEED: For anyone willing to help, I am looking for a logical sequence of tests and perhaps parts replacements from cheapest/most likely ... to most expensive. I figure working through such a series of steps will still be cheaper (and much more macho) than going to a dealer.

    Hope someone out there can help me preserve my sanity... and my quickly-dwindling sense of manhood.
    MervPriusvLights.jpg

    MervPriusvLights.jpg
     
  2. Raytheeagle

    Raytheeagle Senior Member

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    Was the the auto store able to read more details into the codes other than the generic P0A80:whistle:?

    Most code readers are generic, which is what the auto parts stores use as they cover most models:cool:.

    Where in Georgia/Florida do you reside:whistle:?

    There are some members there that have techstream and might be willing to assist, potentially @TMR-JWAP :).

    You'll need more specifics on the codes though to know exactly what the issue is. Techstream is the correct tool for that (y).
     
  3. sam spade 2

    sam spade 2 Senior Member

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    You have a car that is a complex piece of equipment.
    For major things, the dealer often is the only one who can properly diagnose problems.
    Guessing and shotgunning parts at it usually is a losing proposition.

    I think that all or most of the symptoms you report point to a bad hybrid battery and you NEED to get a proper diagnosis from a Toyota shop.
    Not all dealerships are dishonest but they all need to make a profit on their work.
    This is NOT your grandfathers Toyota.

    And.....disconnecting the 12 V does not "fix" anything. It just erases the error indications and they come back again after running for a bit.

    The picture you posted might be cute.......but that is a lot like saying "I don't want to see a doctor for my chest pains because he might tell me I am having a heart attack." :eek:
     
  4. Merv Himself

    Merv Himself Junior Member

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    Currently near Plant City, Florida. Am I wrong to believe an OBD-2 scanner won't work?
     
  5. Raytheeagle

    Raytheeagle Senior Member

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    Plant city is near Tampa:).

    @TampaPrius.com is near there;).

    Might be worth a private message and checking with Todd(y).
     
  6. Merv Himself

    Merv Himself Junior Member

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    Thanks, Sam. Yes, as I noted in my post, I realize what disconnecting the 12v battery does. However, do you really think disconnecting a 12V battery will suddenly make a bad hybrid battery functional again? Or a coolant pump? IMHO it doesn't make sense that a 12v disconnect/reconnect allows me to drive for several days with no issues. And, importantly, how can a bad hybrid battery be giving me 50+ MPG? These are the puzzling questions that haunt me. :(

    You're definitely right though, regarding the complex nature of hybrid vehicles. Or cars in general for that matter. So, I can't just hit this thing with a hammer and make it work? :)
     
  7. jzchen

    jzchen Senior Member

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    The bottom line is the free code readers at the auto stores don't always read the correct code. Had it happen to a friend when we took his '14 Mercedes E-Class to AutoZone. Get a more reliable code reader and start from there. The HV battery bars don't lower or rise as I drive around, because I drive around with a smooth pedal application. The only time it will start dropping is when there is a stop, or stop and go traffic. You aren't out of the woods regarding the battery pack, but you should confirm with a Techstream first as suggested.

    moto g(7) power ?
     
    #7 jzchen, May 9, 2020
    Last edited: May 9, 2020
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  8. rjparker

    rjparker Senior Member

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    Merv Wants to fix it Himself
     
    #8 rjparker, May 9, 2020
    Last edited: May 9, 2020
  9. jzchen

    jzchen Senior Member

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    In this case it is quite obvious that it is wrong, you have at least 3 lights, but the code reader is only giving you one single code....

    moto g(7) power ?
     
  10. Merv Himself

    Merv Himself Junior Member

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    Thank you. I might look into that battery fan. Again, I'm just trying to apply a little common sense here and do an initial inspection of the most likely culprits. It does not make sense to me that a bad hybrid battery would consistently give me 51MPG. It charges just fine. No purple bar readings on this battery ever.

    If the code scanner you recommended is reasonably priced, sounds like that would be a good thing to have.
     
  11. ChapmanF

    ChapmanF Senior Member

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    It doesn't. The car doesn't realize it's sick until particular sensor readings pass particular thresholds (in the repair manual—more info—these are called "detection conditions"). When detection conditions are met, it will log trouble codes, light dash lights, and often change into a protective take-it-easy mode because it knows it is sick.

    When you unhook the battery you cause it to forget that it is sick and forget to behave protectively.

    That lasts until the next time a sensor value crosses a detection threshold and it finds out it is sick again.

    It is as if you have had a high fever and cough and determined you need to take care of yourself, then somebody waves a magic wand and makes you forget all that, so you rush back out to the volleyball court or whatever, but eventually you cough or feel feverish again and realize you shouldn't be there.
     
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  12. Merv Himself

    Merv Himself Junior Member

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    Well, here's what I'm thinking.
    Well, here's what I'm thinking. Since I had disconnected the battery, that could be why the codes were wiped. And perhaps since the "REPLACE HYBRID BATTERY PACK" code says "PERMANENT" , it can't be wiped. Thinking I should probably muster up the guts to drive this thing to autozone next time all codes are lit up but NOT reset the 12v battery first.

    That might give me different scan results.
     
  13. Merv Himself

    Merv Himself Junior Member

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    PLEASE NOTE: Thank you to everyone trying to help. It is my intention to get more accurate codes. However, I would rather not have this thread morph into a discussion of code scanners. Mostly looking for logical advice from someone who can make sense out of the circumstances I have described.

    Also, please note that I have great respect for the many years of experience some of you have. But advice such as "you need to take it to a dealer" does not help me.
     
  14. ChapmanF

    ChapmanF Senior Member

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    If it's four months now you've been playing this game, you might eventually achieve a popping noise and bad smells from the back of the car, which will not be cleared by unhooking the battery.
     
  15. Mendel Leisk

    Mendel Leisk Sand Pounder

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    I think it's valid advice. They'll charge maybe $75 for a half-hour's diagnostics, read all the codes, offer a course of action. Hopefully.
     
  16. Merv Himself

    Merv Himself Junior Member

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    So... is this your way of suggesting I should test the hybrid battery? Or am I missing the nature of your recommendation.
     
  17. Merv Himself

    Merv Himself Junior Member

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    Thank you. Maybe I need to shop around for a good diagnostic place. Because I'm pretty sure $75 won't even pay for a cup of coffee at my local dealer. What are your thoughts about simply scanning it myself with the appropriate tool?
     
  18. Raytheeagle

    Raytheeagle Senior Member

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    Have you called Todd at @TampaPrius.com yet:whistle:?

    He'd be my first call since you are in the area;).

    Good luck and keep us posted(y).
     
  19. ChapmanF

    ChapmanF Senior Member

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    My thought would be that's a fine idea.
     
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  20. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Take a look with Dr Prius?
     
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