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Triangle of death problem

Discussion in 'Generation 1 Prius Discussion' started by Mary12830, Jul 15, 2014.

  1. Mary12830

    Mary12830 New Member

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    One
    I have a 2001 Toyota Prius with about 249000 miles... The red triangle with the exclamation in the car symbol comes on at irregular times while driving the car. Sometimes the car loses power, sometimes it accelerates, sometimes it keeps working, but the light stays on. When we turn the car off 3 times the triangle light goes away and the check engine light comes on. The first time this happened we found nesting material from a small rodent in the engine compartment. We cleaned it out and the lights went away, but we took it to a dealer anyway and they got no information. The red triangle has happened several times since then and the only info the dealer got was that cell #10 in the big battery is losing charge, but when they check the individual cells they are all fine. They say we need a new battery even though the cells seem to be fine. This battery is less than 3 years old and has about 30,000 miles on it (this is our second battery - the first one lasted 10 years and more than 200,000 miles). The triangle comes on now just about every time we take it out for any distance , but it always keeps running after a short rest.
     
    #1 Mary12830, Jul 15, 2014
  2. ericbecky

    ericbecky Hybrid Battery Hero

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    You describe a classic case of a failing battery or a bad sensor wire.

    Failing battery:
    Like any weak battery, if you put it under load, the battery voltage droops.
    This droop in voltage catches the attention of the Prius system that monitor voltage.
    If the voltage droop is severe enough the car will send a warning to you via the dash light.

    Once your car rests a bit, the voltage may bounce back up to an acceptable level, and the monitoring system is happy.

    But once you put the weak battery under load, the whole cycle starts over.

    Eventually you will damage the battery enough that it won't let you drive it at all, and you will be left stranded.I
    It is better to address the problem sooner rather than later.

    Failed sensor wire:
    This is quite a bit more tricky to track down and can cost you quite a bit of labor charge if you have someone else doing it for you.

    You mention that the "...when they check the individual cells they are all fine". But I'm not sure what they actually did. did they open the pack and inspect the modules, or simply rely on the sensor data via their scan tool. If they actually opened the pack and measured the voltage of each module individually of with a voltmeter and found everything to be ok, I would suggest going back in and check the sensor wires too. They can have corrosion or breaks in them that cause false readings. This is best repaired by replacing the entire harness.

    In either case, if this is repair you want to take on yourself, I can point you in the right direction and provide advice.
    Or if you have a trusted independent mechanic, I can help them work on your car as well.

    Best of luck and feel free to call me.
     
    #2 ericbecky, Jul 15, 2014
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  3. Mary12830

    Mary12830 New Member

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    One
    The checked each cell and gave us a reading of each one. They were all about the same. The cell that was reading low had the highest rate of all of them. does that indicate a harness? I don't know if they replaced that when they replaced the battery a couple of years ago.
     
    #3 Mary12830, Jul 19, 2014
  4. bisco

    bisco cookie crumbler

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    was the battery pack replaced with a new one, rebuilt or used? who is doing the checking, a toyota dealer?
     
    #4 bisco, Jul 19, 2014
  5. Mary12830

    Mary12830 New Member

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    I believe it was a new battery and it was done by a Toyota dealer
     
    #5 Mary12830, Jul 20, 2014
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    A new battery would come with new busbars and sense wiring.

    It sounds like the battery case needs to be opened up for inspection.
     
    #6 Patrick Wong, Jul 21, 2014
  7. ericbecky

    ericbecky Hybrid Battery Hero

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    Agreed. The new pack would come with new bussbars.
    Doesn't mean it can't fail, but it is unlikely.

    I would want to see the voltage data while the car is put under heavy load. That is when cell anomalies are more easily seen. Resting voltage is not always the best indicator.

    Rather than relying only on what the instruments are saying the voltage is, I'd want reconfirm it by taking the readings directly from the modules.
     
    #7 ericbecky, Jul 21, 2014
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