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Traction battery and the P0A80 code…

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PNorth, Mar 9, 2022.

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  1. PNorth

    PNorth Junior Member

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    One of the Dr. Prius screenshots shows the Full Battery Test, and the test stalled at the “Check Temperatures” stage indicating “Warning! Battery too cold to continue the test (77F)”.

    Even after the car had run through the Life Expectancy Test, and the car was warm, it still wasn’t warm enough for the Full Battery Test. I live in Canada, and it’s a long shot to get an outdoor temp of 77F right now. Will the battery warm up with the car running, or can this test only be done in the warmer months?
     
    #21 PNorth, Mar 19, 2022
  2. ChapmanF

    ChapmanF Senior Member

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    The car measures both the battery temperature (in a few places) and the temperature of its "inhaling air" (yes, that's how the English translation in the repair manual came out :)).

    The battery itself should get warmer just through being used as you drive, and the air it "inhales" comes from the cabin through a vent by the back seat, so you should be able to warm up that air using the cabin heater.

    That said, I've never tried to use Dr. Prius in such circumstances, so I don't know if it is looking only at those temperatures, or if it takes other things into account.
     
    #22 ChapmanF, Mar 19, 2022
  3. PNorth

    PNorth Junior Member

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    Update:

    So, today I removed the battery from the car, and removed all the buss bars, cleaned all corrosion from the buss bars (soaked in white vinegar and used a fine abrasive buff/sponge on the Drexel to clean and polish. Also soaked the buss bar nuts in vinegar.

    I reassembled the vehicle, and it didn’t throw any codes at me for a while, but they did come back. Now, in addition to the P0A80 and the P3000, I’ve also got a P3017 (High Voltage Battery Module 7 Fault; Battery block 7 malfunction). Is the P3017 specific to module 7, or is it generic and in this case happens to be module 7?

    How can I tell if the problem is just the battery, or if there is also a problem with the hybrid battery ECU?

    Also, I still couldn’t run the Dr. Prius Full Battery test because it kept seeing the battery temperature as below 77F, yet all three temps were warmer than that (see images below).

    Here’s some images of my day:

    7B7EB517-0ABE-4E53-BE1C-84CF009C50F0.jpeg B02A0F56-C454-4BAB-B4C3-AEAB7F96A4D2.jpeg 843E216C-F58E-4473-A2CE-770BF8F641E4.jpeg 467C581C-17E8-4307-9BC4-CC9FDD56DD29.jpeg A700F1CF-DF4B-4738-A01F-C5A05F8F87DD.jpeg 6D288DA3-64D3-4A70-9E71-33364928F15D.jpeg 1590B196-E751-423E-B713-7AFAE5D7936C.jpeg 6753B57C-E67A-4030-B0E8-8F2714806402.jpeg 5D87399C-74AB-4271-BFA2-FB4D2362A42D.jpeg 56963052-3C05-4D3B-B547-D23297E61264.jpeg C8111D19-D779-4748-8F03-F6F1C84F1D11.jpeg 12452955-67CA-40EF-8ECA-DE000E94EDA9.png E8C9A1A1-127F-4F55-B9B2-DC01CE24678C.png FE3A78E4-E645-465A-A8EA-CD36C7A41B7F.png
     
    #23 PNorth, Mar 31, 2022
  4. ChapmanF

    ChapmanF Senior Member

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    Well, P3017 is in the P3 range, not standardized by SAE, so it is a code you had better look up in a Prius repair manual if it was reported by a Prius.

    [​IMG]

    When you look it up in the Gen 2 repair manual, you see that its fortune cookie is "battery block 7 becomes weak" and its detection condition explains "presence of a malfunctioning block is determined based on the voltages from the battery blocks."

    Don't skim over the word "block" there. The battery's voltage-sense wires attach to every second module, so the voltages are measured in blocks of two modules each. Since a module's nominal voltage is 7.2, the nominal voltage of a block is 14.4, and a problem in the seventh block means a problem in the 13th or 14th module (or both); that's the closest you can pin it down from the built-in voltage readings.

    This is your most specific code; the other two codes you have are levels of zoom-out from this one. P3000 is a code from the HV ECU saying the battery ECU has reported some kind of problem with the battery; P0A80 is the code from the battery ECU saying the problem is that some block (or blocks) became weak, and your P3017 is telling you which block.

    The listed "trouble areas" have to include the battery ECU just to cover the possible case where you go and measure all the block voltages yourself with a meter and find they're all ok and the ECU is measuring them wrong, which would force you to conclude the ECU was messed up. But, generally speaking, ECUs are built of hunks of silicon that fail about as often as rocks do, and the trouble codes they report are telling you exactly what the manual says they are.
     
    #24 ChapmanF, Apr 1, 2022
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  5. PNorth

    PNorth Junior Member

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    Thanks so much, ChapmanF!

    Here’s another little nugget of information: I found that when you clear the codes, the triangle and dash warnings would obviously go away, and not return until I shut off the car, and then restarted it. When driving it last night, trying to get the battery temps up to 77F so that I could do the full battery test on Dr. Prius, the codes popped up while driving the car (not after a shutdown), and the HV battery fan turned on. This was after the temps reached 83.16F, 88.40F, and 78.97F as is the image posted above.

    I’m not sure if I have ever actually heard the HV battery fan running before (is it variable speed?). Can a bad battery block cause increased heat?

    Many thanks! I appreciate your help!
     
    #25 PNorth, Apr 1, 2022
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    Going back to post#20, the capture shows block 7 at about 1.5V lower on discharge AND 0.5V higher on charge. That is almost 100% certain diagnostic of a failed cell in one of the two modules in block 7.

    A failed voltage sense harness (or corrosion at the orange connector on the battery ecu) can cause incorrect voltage readings, but that can't cause those exact results. Usually it gives weird very high positive and negative readings on ajoining blocks.

    The battery ecu is programmed to kick the fan up to high speed when it detects certain faults. The fan has 6 speeds and you normally may never notice it depending on your climate and use.

    Posted via the PriusChat mobile app.
     
    #26 mr_guy_mann, Apr 2, 2022
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  7. PNorth

    PNorth Junior Member

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    Thanks mr_guy_mann!

    I appreciate the clarification. I think I’m going to buy a couple of modules (another post recommended 2nd Life Battery in Oregon), and see if that solves the issue. I’m also going to start putting some money aside for a full battery replacement in the future.

    Are the blocks counted starting at the ECU end or the other end?

    I’ll post an update after replacing the modules.
     
    #27 PNorth, Apr 2, 2022
  8. dolj

    dolj Senior Member

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    The other end in a Gen 2.
     
    #28 dolj, Apr 3, 2022
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  9. PNorth

    PNorth Junior Member

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    So this is the block (7) that’s failed, and that I should replace one of the modules?

    349D79FB-1EDC-47E0-8FCB-858ABCC458DE.jpeg
     
    #29 PNorth, Apr 3, 2022
  10. dolj

    dolj Senior Member

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    Correct. With a bit of luck, if you measure the voltage of each module, one of them will be 1.2 V or lower than the other.
     
    #30 dolj, Apr 3, 2022
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  11. PNorth

    PNorth Junior Member

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    Hey folks,

    So my replacement modules arrived from 2nd Life Battery, and I pulled the hybrid battery from the car again. I tested all the modules, starting closest to the ECU:

    655DE1B8-6983-4463-8D13-5C3380E243F3.jpeg

    Block #7 was the obvious problem but block #13 also had a module below 7v, so I replaced both module #4 and module #16 (and I’m wondering if module #19 is going to be a problem soon?). The replacement modules from 2nd Life Battery tested at 7.96v and 7.98v.

    Put it all back together, powered it up, and the car’s back in business! Thanks to everyone for the help and support! It was a fantastic learning experience!
     
    #31 PNorth, Apr 29, 2022
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