Severe power loss on hill climb

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by andrewclaus, Jun 26, 2013.

  1. andrewclaus

    andrewclaus Active Member

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    My 2007 Prius has 120,000 miles. I live in a mountainous area. I need to climb 3 miles at 6% grade to get out of my neighborhood. Lately I've been noticing the traction battery loses charge fairly quickly and I've been thinking about replacing the battery. Much of my driving is in steep hills and I run a full charge cycle many times a day, so I guess I should expect some loss of life.

    But today about half way up the hill the car completely lost power. The engine stayed running but I could not continue forward. I backed onto the shoulder, let the car run in neutral for a few minutes to charge the battery, and was able to finish the climb and drive the rest of the day. It seemed I had very little electric power and the engine seemed to work harder. Fuel efficiency was lower than normal too. There have been no warning lights. I have not been able to check for codes yet.

    This evening I took apart the battery cooling fan and found a nominal layer of fine dust. I tried the hill again with a warm engine and it went just fine.

    Any ideas?
     
    #1 andrewclaus, Jun 26, 2013
  2. nh7o

    nh7o Off grid since 1980

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    Without codes, no one can say for sure. It does sound like a battery or temperature problem. When the battery gets hot, the hybrid system will not allow much current to pass through it. The car will still run OK on the flats.

    Have you had the inverter pump replaced? Check to make sure there is turbulence in the coolant reservoir while the car is in ready mode. Since you are in a hot climate, the statistics point at a reduced HV battery life.
     
    #2 nh7o, Jun 27, 2013
  3. kammssss

    kammssss Member

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    Could it be the HV ECU? This thing is suppose to not let the battery drain that low, right? I have the same problem. Hoping it is the ECU vs. the HV battery.
     
    #3 kammssss, Jun 27, 2013
  4. andrewclaus

    andrewclaus Active Member

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    Yes, I had the coolant pump replaced last year (10K miles ago) under the recall.

    Thanks for the tip on the ECU. I'm thinking about going ahead and replacing the battery (found a rebuild locally for just over $1000) and then checking things out.

    I had no red or yellow lights during the event and I wonder why.

    Thanks for the tips so far.
     
    #4 andrewclaus, Jun 27, 2013
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    If the gear selector is in N, the traction battery will not be charged because MG1 is electrically disconnected.

    If you want to charge the traction battery quickly, you should leave the gear selector in D and hold the car stationary by applying the brake pedal with your left foot. Then floor the accelerator pedal with your right foot. The engine will spin MG1 which will charge the traction battery via the inverter. This "force charging" technique potentially will overheat the transaxle so use it sparingly and at your risk.
     
    #5 Patrick Wong, Jun 27, 2013
  6. andrewclaus

    andrewclaus Active Member

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    I do remember reading this long ago, perhaps in the owner's manual, and thanks for confirming it. But I did notice the energy monitor display showed the ICE charging the battery directly while in Neutral so I let it run that way. The SOC indicator did not change status. Perhaps there's an error in the MFD driver. Or more likely I'm just confused about what I saw or did. In any event, I was relieved to get back on the road fairly quickly.
     
    #6 andrewclaus, Jun 27, 2013
  7. uart

    uart Senior Member

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    Still check it!
     
    #7 uart, Jun 27, 2013
  8. andrewclaus

    andrewclaus Active Member

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    An update: Yesterday I installed a battery salvaged from an '08 wreck with 60K miles. It cost me $700 on Craig's List. The car is working like new again. I never did get a warning light, so I didn't get codes checked.

    I was wrong here--the selector was in P when the engine was charging the battery. I reproduced that situation yesterday.
     
    #8 andrewclaus, Jun 28, 2013
  9. stevejenks

    stevejenks New Member

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    i have a 04 prius only 83900 miles i am having issues with climbing hills myself , toyota wants a 120 just to diagnos , ugh,
     
    #9 stevejenks, Apr 13, 2017
  10. bisco

    bisco cookie crumbler

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    welcome!
    no issues on the flat? mpg's fine?
     
    #10 bisco, Apr 13, 2017
  11. stevejenks

    stevejenks New Member

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    yes the flats it runs great , mpg is great .why i bought the car i have a
    03 dodge dakota my main drive to town know cause their are a lot of
    hills between kekaha and lihue hawaii ,,
     
    #11 stevejenks, Apr 13, 2017
  12. bisco

    bisco cookie crumbler

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    sounds like it might be an engine issue, more than battery. how many miles have you owner her for, and how many miles ago did it start happening?
     
    #12 bisco, Apr 13, 2017
  13. stevejenks

    stevejenks New Member

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    #13 stevejenks, Apr 13, 2017
  14. bisco

    bisco cookie crumbler

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    that's what we all want to know.:cool:
     
    #14 bisco, Apr 13, 2017
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    What is the condition of the engine air filter? Look at the bottom which accumulates dirt.
     
    #15 Patrick Wong, Apr 13, 2017
  16. patcoghm

    patcoghm Junior Member

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    #16 patcoghm, Oct 9, 2017
  17. patcoghm

    patcoghm Junior Member

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    If you still have the car and the same loss of power on hills, I changed the VVT "Oil Conrol Valve" and I solved the problems you describe.
     
    #17 patcoghm, Oct 11, 2017
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