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Is my traction battery going bad?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jdonalds, Jun 28, 2015.

  1. wjtracy

    wjtracy Senior Member

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    My better half also has that feeling, I am under some pressure even though there is nothing wrong with our battery right now. Those of us who are aware of the sudden death batt behavior perhaps become comfortable with it, but my wife is having trouble living with the idea that one day the car may die (throw a Red Triangle). Hope I am driving that day, and I hope it happens at a convenient time.

    Anyway see my thread on Toyota Goodwill Warranty. You could try explaining to Toyota that you would like to do a preemptive replacement and see what they can offer. Keep in mind in your case, if you got the Red Triangle, I would bet full coverage by Toyota at 151k miles in a CARB state.

    HV Battery Goodwill Warranty Listing - Toyota Prius USA | PriusChat
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Wait a sec, that's Positive Crankcase Ventilation valve.
     
  3. bisco

    bisco cookie crumbler

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    isn't that the pcv?
     
  4. jdonalds

    jdonalds Active Member

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    I have A-Fib, an irregular heart beat. I've had it for 15+ years and have had three heart procedures, looking now at my 4th procedure. Over all of those years my A-Fib isn't persistent; it comes and goes over 24 hours. The number of times I was in the doctor's office and they took an EKG showing my A-Fib was about 5% or less. I finally bought my own EKG/ECG machine and emailed strips to my doctor showing the A-Fib behavior. This is pretty much what happened at the Toyota dealer today.

    For $69 the technician reset my mpg gauge and took the car for a 7 mile drive after which he got 43 mpg (which he thought was good. Perhaps it is for a heavy foot driver). He said there were no codes which I already knew. Pretty much a waste of time and money.

    We took the car in about noon. All morning when my wife drove the car, and for me taking the car to the Toyota dealer the car performed perfectly. The avg mpg was creeping up and was about to rise above 40 mpg. This is when the Toyota dealer got their hands on the car declaring it problem free. Wouldn't you know it when I went out to drive the car away from the dealer the battery level showed two purple bars. The mpg sucked on the way home, averaging 25 mpg.

    So we are going to drive the car for a few weeks, keeping an eye on it as we always do.

    By the way they changed the plugs today. First time in 151K miles. They said the plug were slightly worn. I didn't notice any ICE behavior change.

    New problem. The outside temp showed 95 degrees on the way home, creeping up to 97 degrees. The outside temp today is about 112-114. Now I have a new problem to look into. I wonder if the technician pulled a wire off the temperature sensor...
     
  5. bisco

    bisco cookie crumbler

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    plugs should have been done at 120k. are you following the maintenance schedule, or just fixing things as they break? it could need a throttle cleaning, or pcv replacement. injectors might be clogged, and etc., or it could be your hybrid battery going south.
     
  6. wjtracy

    wjtracy Senior Member

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    I did my plugs DIY at 135k miles. The iridium tip is amazing stuff, I hate to think about throwing away the plugs with the itidium on there. The main thing is the plugs are hard to get out after waiting so long. I did not notice a big difference.
     
  7. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Dealers just do not care enough about your problem. Their only problem is how to get some or more of your money. The charge and discharge test I described is a variation of what can be found in the official Toyota service manual. If the technician had followed the book he would have done a very similar test. The results could have shown a weak battery that has not yet reached the threshold of throwing a code. They missed an opportunity to get more of your money. They could have charged more for doing a proper test and most likely sold you a battery.

    I understand your position of placing a value on reliability. I rebuild batteries. For me it is easy. For most it is scary and expense. Every time I drive one of my Prius across country I have a few battery modules and the hand full of tools needed to swap one out. That could make the difference between being totally stuck and a couple of hours repair. For you that same level of security could require the replacement of the HV battery before it is completely dead.

    Owning a Mini VCI cable puts you in a position of knowledge. It does not mean you have to do your own repairs, but that you will know what needs to be repaired. The cost is less than half of what you spent at the dealer today.

    In the last year I have replaced two failed battery ECU's. They do fail and can be difficult to diagnose. It can seem like the battery modules are failing. A new battery from Toyota does not include the ECU. Some dealers will recommend a new ECU with the new modules. Those are dealers who have learned how to get more of your money.;)

    Brad
     
    #27 strawbrad, Jul 1, 2015
    Last edited: Jul 1, 2015
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  8. wjtracy

    wjtracy Senior Member

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    43 MPG by itself is not good, but the car does not even warm up until 10-minutes, so not too shabby for a cold car. Also what I look for is not trip MPG, but if you start hitting 50+ MPG segments on a straight away after warm-up, then I think the Prius is working OK.
     
  9. jdonalds

    jdonalds Active Member

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    Having driven 70 miles now, a mix of city and highway, we are averaging 35 mpg. It seems the ICR runs much more than historically, charging the HV battery. When the HV kicks in to support the ICE there isn't as much power.

    I just wish the car would throw a code and light up the triangle so I could move on.
     
  10. SageBrush

    SageBrush Senior Member

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    ^^ Have you logged your battery module voltages while driving ?
    I presume you have already excluded a weak 12v battery.
     
  11. jdonalds

    jdonalds Active Member

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    I do not have the capacity to log the module voltages. Is that something I can do with a VCI cable and Techstream?

    We replaced the 12V battery with an Optima battery in 2014.

    I just ordered a VCI cable and Techstream CD. Seems like the next logical step based on everyone's input.

    Thanks to all.
     
  12. SageBrush

    SageBrush Senior Member

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    Yes
     
  13. uart

    uart Senior Member

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    It's definitely worth checking it though. It will have something of a "threshold" type behavior, as in it will reach a point where it will suddenly try to use the HV battery much less because of the temperature.
     
  14. strawbrad

    strawbrad http://minnesotahybridbatteries.com

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    Run the charge and discharge test without The Mini VCI cable and Techstream. A good battery can take 5 minutes to go from full green bars to a couple of blue bars. A weak battery could do that in just a minute. That is not a very accurate measurement but it is something to do while waiting for the cable.

    Brad
     
  15. bisco

    bisco cookie crumbler

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    and double-check the 12v just for funnies, it's cheap and easy.:)
     
  16. SageBrush

    SageBrush Senior Member

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    Reporting a drop in fuel economy should be followed by a reasonably standardized test we can relate to:
    1. Warm engine
    2. Happy SOC range - about 5 bars
    3. 5 mile to, 5 mile back trip at 60 MPH
    4. No braking
    5. Little wind
    Before the test check tyre pressures, engine air filter, and hand brake.

    A healthy Prius manages around 60 MPG
     
  17. jdonalds

    jdonalds Active Member

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    I agree. We've easily gotten 60 mpg under those conditions. Right now I'm having difficulty even reaching 40 mpg under any conditions.
     
  18. jdonalds

    jdonalds Active Member

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    Okay sounds reasonable. But how does the 12V battery effect mpg?
     
  19. jdenenberg

    jdenenberg EE Professor

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    A very weak 12v battery pulls heavy current from the 12v bus while you are in Ready Mode and dissipates the energy as heat.

    JeffD
     
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  20. bisco

    bisco cookie crumbler

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    what he said. ^^^