Engine maintains high rev with foot off the gas pedal

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Matt Hinkle, Jan 2, 2019.

  1. Matt Hinkle

    Matt Hinkle New Member

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    Even since I replace the hybrid drive battery the ICE sometimes will hold high revs at a stoplight or while decelerating. The state of charge seems to stay on the high side, where as sometimes with the old battery it would dip into the purple bars. It will also sometimes at stop light start and stop the ICE repeatedly. None of this relay seems at affect acceleration or just normal driving. Has anyone had this issue? I currently have no active or stored trouble codes and the battery was replaced for the bad cell code and red triangle. When the battery was installed, the installer was getting weird “no communication” codes in his reader and suggested a new 12v battery. After he left I powered the car up and it had no codes and ran pretty normal. I did replace the 12v battery.
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Tell us more about this replacement HV battery, was it a New Toyota OEM battery or something else?

    What you are experiencing is the vehicle bleeding off the extra charge, this happens when the battery is at or near 80%
     
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  3. JC91006

    JC91006 Senior Member

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    I'm suspecting your replacement battery is not balanced, voltages are all over the place. To fix this issue, you would have to make sure all the modules in the battery pack are good and that you balance the battery.

    The high revs is a bit strange though
     
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  4. Matt Hinkle

    Matt Hinkle New Member

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    It is a re-manufactured HV battery. I don’t understand how the engine holding high revs bleeds off excess battery charge. It seems to me it would just charge it.

    Is there a way to check voltages without removing the battery? It does have a good warranty so maybe if I can prove the battery being out of balance I can get another one.
     
    #4 Matt Hinkle, Jan 3, 2019
    Last edited by a moderator: Jan 3, 2019
  5. SFO

    SFO Senior Member

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    Without the proper DTCs (codes) being thrown it is unlikely that you could get any kind of replacement.

    Of course it never hurts to ask, and they can explain the warranty if needed.

    Do you have a ODB2 code reader, if not then now would be a great time to pick up such. A proper reader can display voltages.

    If you have a laptop/computer then grab a mini-vci cable with techstream for $20, or a smartphone you can get a bluetooth adapter for $2.
     
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  6. JC91006

    JC91006 Senior Member

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    How do you know it's revving at high speed? The car doesn't have a tachometer.

    I would check your air filter, make sure that's not clogged. Also clean the MAF sensor and throttle body. These items will cause idle speed issues when they are dirty.

    Concerning your battery, it may be normal for the battery SOC to not dip into the purple area often. A good battery will normally operate with 5 or 6 bars on the SOC at all times. It won't go too much above or too much below that. But with any refurbished battery, it's not going to be perfect.
     
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  7. edthefox5

    edthefox5 Senior Member

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    better get used to it you got the re-manufactured battery blues.

    You do know the word "remanufactured" means they put the same age modules in there and hope and pray it makes it out of the warranty period they offer. Most are tail light warranty's. There are no new battery modules available so they are pulled out of wrecked Prius's. Only way to get brand new battery modules is by buying the entire hybrid battery brand new at the dealer. $$$$.

    What you have is commonly refereed to as a whack-a-mole repair.
     
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  8. JC91006

    JC91006 Senior Member

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    You can look at live data using Techstream software. There may be other apps that can show that as well. It'll show all 14 blocks and it's operating voltages
     
  9. Matt Hinkle

    Matt Hinkle New Member

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    To clarify, if I’m decelerating from high speed (55mph or higher), when I take you foot off the accelerator the engine maintains the same revs instead of dropping to idle or turning off. And it seems the regenerative braking isn’t as aggressive. And sometimes at stop light the end will rev to what sounds like high way revs and hold it for about 20 seconds or so. None of these things happened before the battery was throwing codes.

    Yeah I was aware of that part. The warranty is for 5 years. I just didn’t expect it to act this funky.

    There are a lot of choices when I search tech stream on amazon, which is the best?
     
    #9 Matt Hinkle, Jan 3, 2019
    Last edited by a moderator: Jan 3, 2019
  10. SFO

    SFO Senior Member

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    Hard to quantify the "best" J2534 pass-through dongle, is it the one that costs $20 or less and generally gets the job done, the $80 VxDiag with additional techstream compatibility, the $169 Tactrix "Made in the USA", or maybe the $495 "official" Mongoose cable.

    Buy something with free return shipping, that way if it doesn't work you can move on to another seller.
     
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  11. priusmod

    priusmod Junior Member

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    I am having the same issue. The Red Triangle is on. HV battery fan is running Max speed. I am assuming that batteries need to be replaced. If I shut the car off and restart it corrects the problem briefly then lurches and goes back to revving the ICE motor at high speeds (no need for a tachometer you can hear it and feel it.) With the HV battery drained in stop and go traffic the ICE motor limps and gets up to speed slowly then the car accelerates on its own like you have described. I am going to undertake replacing the HV batteries and hope to rectify this acceleration issue as well.
     
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  12. priusmod

    priusmod Junior Member

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    I have replaced the HV battery today and the high revving has stopped. Hopefully I will have increased gas millage as well.
     
  13. priusmod

    priusmod Junior Member

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    Out with the old in with the new.
     

    Attached Files:

  14. SFO

    SFO Senior Member

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    Which HV battery did you end up installing yourself (or have someone install for you)?

    Judging by the color of your replacement HV battery case, was there a reason you didn't purchase from :

    http://hometownhybrids.com/

    or

    Texas Prius Battery Replacement

    Please keep us posted on how that replacement works out for you.
     
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  15. priusmod

    priusmod Junior Member

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    I went with Greentec. I installed it myself. I ordered it on Monday it showed up on Wednesday and put it in today. It took about three hours. I wasn’t aware of the other hometown or Texas hybrid. I’m from Texas! I went with all new batteries in the case and it has a four year warranty. I did a lot of research and it seemed that changing out the whole case was the best solution rather than changing out all the individual batteries. Having a look at the batteries in the case they are not what I expected. Much better actually. There isn’t a vent tube assembly as expected. They are closed sealed. I cleared codes buttoned up the panels and everything is working great. I purchased a Bluetooth obdII dongle and an android tablet to run Torque Pro to monitor systems. I’m looking forward to seeing what sort of MPG the car will get. I will post results in a month to let you know how well it is functioning.
     
  16. Raytheeagle

    Raytheeagle Senior Member

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    How do you know the modules are “all new”? Did you look at the modules to get a date to code confirm your purchase and your perception?

    Typically the modules are used and they may balance them prior to presenting your purchase in a nice green case.

    Good luck and keep us posted (y).
     
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  17. Kevin_Denver

    Kevin_Denver Active Member

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    Does the engine staying rev'd happen only when the battery is showing 7 or 8 bars? If so, this is normal operation - the computer won't let the battery stay above ~80% state of charge as doing so would lessen the lifespan of the battery. Therefore if it gets heavily charged from braking a long time (like from 55mph), it will spin the engine with the electric motors (without using any gas) to let off the excess charge. Note that 1 bar indicated equates to a ~40% battery charge and 8 bars to ~80%.

    The computer will also keep the engine rev'd if detects the hybrid battery is failing (accompanied by warning lights and code).
     
  18. qettyz

    qettyz Active Member

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    If getting old laptop and installing software etc doesnt feel good to just check voltages.
    Then Android phone with HybridAssistant app with HybridReporter may be handy. It works with these cheap OBD2 bluetooth adapters and can perform HV battery check routine for example.

    It logs all invidual voltages during driving and show then logs with voltage differences etc.
    Also engine loads, rpms, SOC...

    Edit: even better: with that one can go for a drive amd log everything. Then upload full html log here. Then diagnosing ones problem would be so much easier. No need asking about high rpms, SOC levels.

    Example log from HybridReportet
    Screenshot_20190120-095754.png
     
    #18 qettyz, Jan 20, 2019
    Last edited: Jan 20, 2019
  19. priusmod

    priusmod Junior Member

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    Yes I could see the modules
    They provide remanufactured options. I went with the new as in brand new cells. I could see they are nothing like the original gen2 cells in the old case. I will keep you posted.
     
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  20. Raytheeagle

    Raytheeagle Senior Member

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    Pics?
     
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