2007 Prius. Hybrid battery (original) failing...

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Danica, Aug 6, 2025 at 7:04 PM.

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  1. Danica

    Danica New Member

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    True, and true. But I just heard back from the dealership. Apparently all the lights came on and the triangle appeared while he had the car out for the test drive. After 35 miles in the heat. So I may have to pony up for the 12V AND the hybrid batteries to be replaced. Crap, crap, crap. The new 12V has already been installed.
     
    #41 Danica, Aug 9, 2025 at 6:40 PM
  2. JC91006

    JC91006 Senior Member

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    This is very typical of how dealerships/any trade works. They replace the easy money items they deemed "failed" and not address the real issue so they know you'll be back.

    It's like calling an AC tech to your house when it's 110 degrees, you'll agree to anything they say is wrong with your AC. They'll replace 5 parts when all you needed was 1
     
    #42 JC91006, Aug 9, 2025 at 6:44 PM
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  3. Danica

    Danica New Member

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    Maybe so. But he sent me a text with a photo of some test they ran on the 12V battery, showing it had failed. At the time, the car was not throwing any other codes, and he said that a bad 12V could cause the P3011 code. So at the time, it seemed like the right decision to go ahead with the 12V installation.

    I just got off the phone with him, and he said the triangle came on just as they were pulling into the dealership. He said the car is now showing two codes: P0A93 ans C1241. The first code is for the inverter cooling water pump (the thing Hayslayer warned me about), and the second code is for the hybrid battery.

    He said that MAYBE if the inverter water pump issue is fixed, that will resolve the apparent issue with the hybrid battery . But he wants to run more testing -- which he said I am not being charged for -- and the tests will all have to wait until Monday morning. He also mentioned something about "before you sink any more money into this" so I didn't get the feeling he's just trying to get as much money as he can from me.
     
    #43 Danica, Aug 9, 2025 at 7:09 PM
  4. pasadena_commut

    pasadena_commut Senior Member

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    Failing when hot is typical of P0A93, but it wouldn't normally take half an hour in 115F heat. A couple of minutes tops, or maybe a minute on the highway. The code can mean other things, any of which make the inverter overheat. In this particular case I suspect that the same thing will be happening after the pump is replaced. Make them check for low coolant and fan problems. "Failed when it pulled into the dealership" could mean "the cooling fans didn't come on when we stopped moving".

    Edit: maybe post the picture of the 12V battery report. If the 12V is not fully charged when a battery test is run the tester may fail it even though it would pass when the same battery was charged. That said, it wouldn't be surprising if the 12V had given up the ghost - high heat kills 12V batteries.
     
    #44 pasadena_commut, Aug 9, 2025 at 8:42 PM
    Last edited: Aug 9, 2025 at 8:54 PM
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  5. Danica

    Danica New Member

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    Thanks for the advice. I hope this works.
     

    Attached Files:

    #45 Danica, Aug 9, 2025 at 9:07 PM
  6. Brian1954

    Brian1954 Senior Member

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    Code C1241 is not about the hybrid battery. The code is detected by the ABS and Electronically Controlled Brake System. The description for the code is "Low Battery Positive Voltage". The 12 volt power supplied to the brake booster is lower than it should be. Do a search for C1241 code in this forum.
     
    #46 Brian1954, Aug 9, 2025 at 9:58 PM
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  7. Hayslayer

    Hayslayer Member

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    Your situation is hurting my heart. That pump costs me about $140 at a dealership. It takes about an hour or less to replace by removing the driver headlight for access. It's been a while since I checked dealer pricing, but a few years ago, they charged around $600 for this job. I can only suspect it's gotten worse. I really hope they're not going to nickel and dime you to death or convince you it's a money pit and you should get a new car. A 130k mile Gen 2 is a diamond in the rough.

    and the 1241 was probably caused when they did the 12v battery swap..they probably disconnected the brake backup power supply while swapping the battery. Hopefully they reconnected it.
     
    #47 Hayslayer, Aug 10, 2025 at 2:06 AM
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  8. Danica

    Danica New Member

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    Thank you. The guy at the dealership quoted me a price of $850-$900 to replace the inverter pump. Rest assured I will NOT get the job done there, at least not unless he significantly drops the price, which I very much doubt he will do.

    Thanks to you and Brian1954 for altering me about the C1241 code, I have been trying to research this and yes, I believe you are probably right that this may be related to the new 12V installation. I will bring this up to the dealership guy when I talk to him Monday.

    I have been warned that the dealership will probably offer me $500 to take the Prius off my hands and tell me I'm better off with a new car. I won't be surprised if they do this.

    Once again I am getting a little ray of hope that maybe the hybrid battery hasn't gone bad after all.

    The dealership guy wants to run more tests on Monday, and he promised I will not be charged for these tests. So at present I figure let's run the tests, see what comes up, and go from there. But unless the dealership offers me some kind of amazing deal on the needed repairs, I am very strongly disinclined to let them do any more work on my car. I've already paid too much for the new 12V.

    Thanks again for all of your help and advice.
     
    #48 Danica, Aug 10, 2025 at 12:35 PM
  9. pasadena_commut

    pasadena_commut Senior Member

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    I'm not familiar with the tool they used. There are DCA-8000 manuals on the web but the one I looked at did not say what it meant by "Ah replaced" or exactly how that test was performed. If that voltage is after the charge then yes, that was a bad battery for sure. I don't see how they could have managed 16.2 "Ah replaced" over only 54 minutes without subjecting the battery to around 16 Amps, which is way, way, way over its specified max of 4 Amps. ("Ah" is "amp hours" - integral over time of input amperage. There is a correction for charging or discharging at high currents but I don't think it would make 4A look like 16 A) It would have been fine to discharge 16.2 Ah out of the battery in a relatively short period though.
     
    #49 pasadena_commut, Aug 10, 2025 at 1:33 PM
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  10. Danica

    Danica New Member

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    I have absolute faith that you know what you're talking about, but all the information on that image, and everything you just said, is way over my head, lol. It's like I'm watching an episode of Star Trek where they're talking about a resonant frequency field to contain a graviton wave for the photon torpedo guidance system. It's all Greek to me.

    At any rate, the deed is done and they've already put in the new 12V battery. But, lesson learned. Unless they give me a great deal on the remaining repairs, which I strongly doubt they will, I will look elsewhere to have the rest of the work done.
     
    #50 Danica, Aug 10, 2025 at 1:53 PM
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