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2009 Very little regen charging at speed

Discussion in 'Gen 2 Prius Technical Discussion' started by A Plack, Dec 5, 2021.

  1. A Plack

    A Plack Junior Member

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    Location:
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    Vehicle:
    2009 Prius
    Model:
    III
    2009 Prius w/ 220k and rebuilt battery. Previous battery had same exact issues. Rebuilt battery passes all Dr. Prius test and shows more SOC than my 2008 w/ 114k. The 2009 ICE has a lifter tick, and occasionally stumbles when shutting down. New plugs and igniters on ICE. Other than the tick and occasional shutdown stumble... ICE purrs just fine.

    If I the battery is at 2 bars, and I sit for 10 minutes with ICE idling, the battery comes up to 4-5 bars. If I place it in drive and hold the brake, the battery will have all green bars within 10 minutes.

    When I drive, the ICE does not start right away. It is not trying to start, but does not start right away. Full charge battery drains to 1 bar in 5 miles. The computer shows mostly electric usage with occasional ICE at 55mph. ICE does get running above 20 mph. If I try to go past the 1 bar, I will get a P0A80 and the car will not go faster than 15 mph on ICE alone. According to the car, I am getting 68mpg during those first 5 miles.

    Once the car warms up, the ICE turns off/on/off/on/off/on/off/stumble/on @ 55mph. If I stop, ICE idles and will charge the battery, then I can go again for another 3-5 miles.

    I have little to no regeneration when down hill with a slight brake depress.

    With 220k and the engine tick, I understand that the ICE may not have sufficient power, but I am thinking that the Traction computer (or something else) is causing a problem.

    Techstream only shows the P0A80 and no other codes. The first battery, doing the same thing would only go 1.5 miles before the problem started with the same code, so I think this rebuild is good.

    My 2007, when the battery went bad, I was still able to drive > 50mph, but my mpg was only 16. Then I couldn't start it.

    Could the transmission or Inverter be at fault here?
     
    #1 A Plack, Dec 5, 2021
  2. bisco

    bisco cookie crumbler

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    idk, if you're getting the code, isn't it the battery?
     
    #2 bisco, Dec 5, 2021
  3. A Plack

    A Plack Junior Member

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    III
    Codes are just idiot lights. I don't trust it because every stat about the battery shows it is better than new and no battery module is outside of .3V The code lights because the entire pack is now discharged. This is why I question the computer.

    If something else is causing the discharge (or lack of regen), then how can the battery NOT have "low voltage" on one or more cells?

    If the code were accurate, why does the car not go faster than 15mph, and why when I shut the car off (and a short pause) does the triangle disappear, the ICE starts and the battery charge?
     
    #3 A Plack, Dec 5, 2021
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    I would be looking at data for the ECM and hybrid control modules (and probably braking control as well). Somewhere is a line of data that tells whether ICE operation is requested or not. Might be interesting to see if the hybrid control wants ICE on and off, or whether the ICE just can't start and run properly. There's also data about regen and whatnot. Have a look around and see what stands out.

    Posted via the PriusChat mobile app.
     
    #4 mr_guy_mann, Dec 5, 2021
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    Some of your post is a bit confusing and making it difficult to grasp your exact symptoms. For example:
    When I drive, the ICE does not start right away. It is not trying to start, but does not start right away.

    A P0A80 code, by itself, will not put the car into limp mode. If you're getting the P0A80 due to something else on the car failing to do its job correctly and causing the HV battery to drain (like the engine not functioning correctly), that problem needs to be resolved first, otherwise you're spitting into the wind.

    The below sentence sounds more like inverter high temperature symptoms.
    If the code were accurate, why does the car not go faster than 15mph, and why when I shut the car off (and a short pause) does the triangle disappear, the ICE starts and the battery charge?

    And then there's always the possibility the engine doesn't want to run. It needs air, fuel and spark. One of those things isn't happening correctly, and it sounds like it's mostly not happening at times when higher power levels are needed. That would likely be air restriction or inadequate fuel/fuel pressure.

    So you have a 'rebuilt' battery that tests as being better than a new battery? That's unusual. What components were replaced on the rebuilt battery? What components weren't replaced? Maybe there's something to look at.

    As always, not being there just means we're all throwing our own guesses into the pile, based on symptoms provided, which are a bit confusing.
     
    #5 TMR-JWAP, Dec 5, 2021
    Last edited: Dec 5, 2021
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