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P0A80 Code- but is it really the hybrid battery

Discussion in 'Gen 3 Prius Technical Discussion' started by Mellyman666, Mar 9, 2024.

  1. Mellyman666

    Mellyman666 Member

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    I was wondering in the mean time, of cleaning and servicing the HV fan cause I doubt the previous owner ever did it. I just want to make sure I can remove the cover circled in my pic without any high voltage worries or electrocution worries lol

    I also found this girl who cleaned her fan and was going to follow her steps. I know it won't fix my problem but I read it will need to be cleaned anyways when changing the HV battery so

    https://blog.machanon.net/2018/02/09/diy-how-to-clean-your-3rd-gen-prius-high-voltage-hv-hybrid-battery-cooling-fan/
     

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  2. Brian1954

    Brian1954 Senior Member

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    You have not answered my question about the battery cooling fan. When the warning lights were visible on the dash and you had the P0A80 code, could you hear the battery cooling fan running at high speed?

    Before you try cleaning the fan, just look in the trunk for any signs of moisture or rust. Do you notice anything that would indicate water getting into the trunk area?

    If you want to tackle cleaning the cooling fan, that is okay and it is safe. All the high voltage is located underneath the metal battery cover, so you can safely remove the plastic cover that is above the metal battery cover. If a dog or cat was transported in the back seat, you will find pet hair inside the fan. If a pet was not in the back seat, you would normally only find some dirt/dust accumulation on the fan blades.

    The cooling fan can run at 6 different speeds depending on the temperature of the hybrid battery. Most times you will not hear the fan running when you are driving the car. The only time you may hear it running is when you get the warning lights on the dash for problems with the hybrid battery like the P0A80 code. When that code is triggered, the cooling fan will be told to run at high speeds. I do not think that you ever mentioned hearing it, so that is the reason I am asking if you ever heard it running at full speed.
     
    Mellyman666 likes this.
  3. Mellyman666

    Mellyman666 Member

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  4. Brian1954

    Brian1954 Senior Member

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    Thank you for answering all my questions. I read through the complete thread again. I have additional question? How often do you use the EV mode? Do you use it while driving in the city or just to move the car in your driveway?

    It does not make any sense to me that you could not here the battery cooling fan running at full speed when the warning lights where on. Do you use the radio at high volume when you are driving?

    Do you have the warning lights on the dash presently? If so, turn the car on and check to see if the fan is running by listening at the intake vent that is located by the right rear seat area by the door. Or put a piece of paper over the vent and see if it sucked in by the fan against the vent.
     
  5. Mellyman666

    Mellyman666 Member

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    I have no warning lights on at the moment BUT only because the Dr Prius app erased them by accident. Before that I had the orange triangle, check engine and check hybrid system lights, same as in post 27. I will do that test as soon as I put the fan back, but before taking it off, I put my car on idle and tried with and without EV button engaged and put my hand in front of the fan and didn't feel much...
     
  6. Mellyman666

    Mellyman666 Member

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    Could those “rust” looking marks on the edge of the battery mean there might be corrosion under?
     

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  7. Brian1954

    Brian1954 Senior Member

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    I do not think so. Your fan did not look too dirty. You might want to keep the top plastic cover off for a while. It will be easier to see if the fan is running like it should.

    Please do not use the EV button at all until the HV battery problem is fixed.

    I want to make sure the battery cooling fan is working.So put the fan back together and turn the car on and hold a piece of paper close to the intake vent and see if the fan sucks it in. Also if you have time, can you please hook up the Innova scanner and check for trouble codes.

    The next time time the warning lights come on, see if the fan is running at full speed (noisy). I am asking these question to try to determine if the problem with you battery might be the battery smart unit.
     
    #67 Brian1954, Mar 20, 2024
    Last edited: Mar 20, 2024
  8. Mellyman666

    Mellyman666 Member

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    I was just about to ask that if I could keep the top cover off the battery (plastic cover, not metal cover!!) for a while to see if the blades actually turn. I just put everything back together. If I put my hand in front of the fan I feel nothing, a paper doesn’t seem to get sucked in either…but I THINK I hear a very faint noise of a motor but cannot be sure
     
  9. Mellyman666

    Mellyman666 Member

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    Plugged Innova back up; all i get is the permanent P0A80 (since the current one was erased with Dr Prius). I’ll check in other DTCs, sometimes they diagnose ones that don’t show up.


    I got a random P0301 (pending)- cylinder 1 misfire (no idea why, didn’t have this before or yesterday when I plugged up innova) last time I did anything in the engine was sep 2023 when I changed the head gasket and haven’t had a problem there since

    B1423 (had it before)
    B1503 (had it before)
    B1660 (had it before)
    The two related to the P0A80 (C1310 and C1259) do not show up anymore, probably since the P0A80 isn’t currently there.
     
  10. Mellyman666

    Mellyman666 Member

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    Also just noticed in live data that my fuel system says open loop. It’s always said closed loop. Maybe related to the misfire code?
     
  11. Brian1954

    Brian1954 Senior Member

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    Correct.

    (I am having router problems on my home network. It keeps rebooting, so I am in the process of going to a backup router. So my posting will be delayed until I get it installed.)

    To see if the fan is working, connect the Dr Prius app again, then go to the special features page and click on "Override battery temperature" then slide the scale down to the lowest temperature which I think is 50F. It might be colder then 50F their, so I do not know if this will work. See if the fan is running.
     
  12. Brian1954

    Brian1954 Senior Member

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    No, I do not think so.
     
  13. Mellyman666

    Mellyman666 Member

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    Cylinder misfire disappeared after restarting the car (it was never a confirmed code). I will do thé dr Prius app test tomorrow as it is already colder than 50f hère this evening.

    My question is, if it’s the fan (or the battery power unit as you say which I’m assuming is responsible for the fan), this would technically cause my hybrid battery to overheat since the fan cannot get rid of the hot temp of the battery? if it is only the fan, could it be it not working will have lead to my battery being crap at this point? Or do you think if it’s only the fan it could potentially be salvaged?
     
  14. Mellyman666

    Mellyman666 Member

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    Might sound like a dumb question but does the HV battery just turn on when in EV mode? I don’t think so since it controls a bunch of other shit but I wanted to make sure. Doing fan testing today. Found a mechanic shop who checks batteries (takes out the HV and checks cells) for like 400$. Debating …
     
  15. Mellyman666

    Mellyman666 Member

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    Update: fan does not work. Tried it idle, driving, using normal engine, using EV mode. At no point did I see the fan moving so unless it auto shuts off when the cover is off or something, but did not move. I do hear some “electrical” noises, almost like something is trying to start or use power but fails..
     
  16. Brian1954

    Brian1954 Senior Member

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    Thank you for the detailed description. Electrical and control systems are not my strong point.

    Do you know if the battery cooling fan is always running at slow speed, even when the temperature is low? I know that the speed will increase as the battery temperature increases.

    So the battery cooling fan is controlled straight from the power management control ECU and does not go through the battery smart unit. I was thinking if the fan is not running, it could be caused by a faulty battery smart unit, but that is not the case based on your description.

    The way I look at it, the unrealistic data shown in the Dr Prius app could be from:
    1. Bad connection of the Veepeak Bluetooth adapter installed in the OBD2 port.
    2. A bad Veepeak adapter
    3. The Dr Prius app itself, but this is very remote possibility in my mind.
    4. Faulty power management control ECU
    5. Communication problem between the power management control ECU and battery smart unit
    6. Faulty battery smart unit
    7. Faulty 12 volt power or ground connection to the battery smart unit. What do you think a faulty ground would do?
    8. Something else that I have not listed above.

    After the P0A80 trouble code is trigger and if the code is not cleared, normally after a few driving cycles, a new trouble code will be displayed like P3017 which tell you the battery block that is bad. This does not seem to have happened, maybe because the ECU can not decide which block is bad because of all the wild data that it is seeing.

    I would love to read your reply to what I wrote above.

    @Mellyman666 , Can you please try the Dr Prius app again to gather more data. I want to see if you still see unrealistic values.
     
  17. ASRDogman

    ASRDogman Senior Member

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    Have you disconnected the fan, and apply 12 volts to it too see if the fan actually works?
    And maybe it is not getting voltage to it?

     
    #77 ASRDogman, Mar 23, 2024
    Last edited: Mar 23, 2024
  18. Mellyman666

    Mellyman666 Member

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    Hi!!

    I tried it again yesterday and I'll attach photos.

    What I noticed:
    1. Battery voltage increases abruptly when braking (don't know if that's normal)
    2. Fan did not come on at any point (it's currently plugged but uncovered - like the black tube attaching it to the vent on the side of the passenger door is off- don't know if that would cause it to not work?). However, I read that below a certain temp, the fan does not work. It's quite cold here (-5 Celsius or 23 Fahrenheit) so maybe that's why it's not working? Cause if you look at my screenshot (the ones here as well as the older ones) my battery never really gets hot.
    3. Like I just said, battery doesn't really get hot. I know it's cold outside, but wouldn't it get super hot if the fan didn't work and it was overheating?
    4. I'm still trying to understand some of the weird Dr Prius app info. Linked below and marked with a pink hand drawn * on the picture, is the Dr Prius more app info I got the other day with the weird data.

    I posted a few Dr Pirus apps from 24-03-22 when I went to try the fan. Like mentioned earlier, if there's a pink asterix, it's from the other day with the weird Dr prius data.

    I did quite a bit of research and found a list of things it might be, before the battery. I'm not saying my battery is in tip top shape, obviously with the age it isn't, but even with my very little knowledge of HV batteries, I just find it weird that all I have is the P0A80 code, with absolutely no symptoms of a bad battery.
    A lot of the 'other causes' I found align with your list, so I will try to see how to test these other things. My husband is really against me opening the battery myself cause he thinks I'll electrocute myself :LOL:, but I'll try to test the things that don't require me removing the battery, and if I need to remove it I'll bring it to a mechanic I guess.

    Let me know what you think of the list of causes I found, there's some that are what you said, but I'd like to know your opinion on the other potential causes I found:
    1. Blower motor controller
    2. Failed battery smart unit
    3. Traction battery ECU
    4. Loose, broken or corroded bus bars
    5. Blower relay
    5. Inverter coolant pump
    6. HVBMS sensor failure

    Another question; is the Traction battery ECU and the battery smart unit the same thing?? Because I heard the traction battery ECU is in the glove compartment??? But earlier someone said they were interchangeable terms I think? I don't know a little lost on that aspect

    once again, thanks a million :)
     
  19. Mellyman666

    Mellyman666 Member

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    I might sound like a total newb right now (I kinda am) but how do I apply 12 volts to the fan? (n)
     
  20. Mellyman666

    Mellyman666 Member

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