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Orange Triangle!/P0AA6/Replace Hybrid Battery?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by El Gato, Oct 4, 2021.

  1. El Gato

    El Gato Junior Member

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    2010 Prius
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    Hey y'all! It's me again!

    I was here two months ago with the EGR issue. I ended up paying $1,576 to replace the EGR Valve, Cooler, and get a coolant system flush and week before that $816 on replacing all spark plugs and coils too. So I just invested $2,400 into replacing parts in my Prius.

    Model Year: 2010 but on the road since August 2009.
    Mileage: 225,000

    Angry triangle! popped up last Thursday with no discernable difference in performance other than a weird stuttering when switching gears (not sure if related). Took it to dealer next day (I know I know, please don’t rag on me for dealer…they give me a free diagnosis and they record the process), Tech told/showed me in video error code P0AA6 and said it was a High Voltage Isolation Fault and that my battery was basically making contact with the body of the vehicle and added that it was extremely dangerous. He zoomed in to show me corrosion on the terminals that we could see. He didn’t check the terminals on the left that were covered or on the back but assumed that those were probably corroded as well. Recommendation was to replace the hybrid battery at the cost of $4,346. (screenshot pics at bottom)

    Question is…can the erosion not just be cleaned like on any 12V battery in car? If replacing is best option, I’ve seen lots of DIY videos on this, and is it truly that easy and how dangerous is this considering the high voltage system? My skill set is rudimentary. I’ll change/replace light bulbs, regular batteries, but that’s the most I’ve ever done. It doesn’t seem like I need any other told other than the power tools I already own?

    Onward to a more pressing question for me…considering the mileage, but the recent investment of the replacement of the EGR system…BUT gotta add some other issues from this visit that came up such as: replacing front brakes, Drive/CV shaft leaking grease and recommendation replacing boot kit, and the big one: Timing Cover leaking (this has been an issue for a while but I’ve been dealing with it…I just top off my oil as need be when it gets low). The big question….time to trade this in and get a new vehicle? If that answer is No, can I can push this baby up to 300k miles? I guess I would replace the battery DIY (unless those terminals are something that can be cleaned or ya’ll don’t recommend DIYing it), go somewhere else to get the boot kit and brakes taken care of (I can’t DIY that stuff), and continue to ignore that timing cover leak like I’ve been doing for nearly 3 years now….Thoughts?
     

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    #1 El Gato, Oct 4, 2021
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Ask him how the corrosion on the terminals is reaching the car body? I'm curious what answer he'll provide for that.

    The answer is that corrosion on the terminals has ZERO to do with a P0AA6. If the DTC subcode points to the HV battery as being the source of the P0AA6, then it is much more likely that one of the modules has a small electrolyte leak that has made contact with the battery case. Often you can see significant areas of discoloration on the metal case where electrolyte has been seeping and spreading for a while. This can typically be resolved by replacing the leaker. Toyota won't do that, but you can if you're comfortable with DIY.
     
    #2 TMR-JWAP, Oct 4, 2021
  3. ChapmanF

    ChapmanF Senior Member

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    Yeah, P0AA6 (that's a zero 0, not a letter O) refers to a high-voltage isolation fault that could be anywhere in the car. They should have started by showing you the INF code that would at least narrow it down to the tranny, the front-of-car electronics, the air conditioner, the wiring, or the battery.

    Maybe they didn't skip that part, and they really did see the INF code for the battery, but I didn't see that basic step mentioned.

    If it is within the battery, and if it's some leaked electrolyte, it might respond to a good cleaning and replacing whatever module is leaking.
     
    #3 ChapmanF, Oct 4, 2021
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  4. rjparker

    rjparker Tu Humilde Sirviente

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    I would get a new vehicle. You really need a rebuilt engine so if you further invest in a battery (assuming its where the hv leakage is), change the cv joints (a good idea once contaminated) and fix the brakes, you still have an oil burner, high potential for a head gasket (slight rattle previously reported), potential brake booster failure and who knows what else (inverter, wheel bearings). Sorry so much was spend on the egr system, its a Priuschat specialty that many Toyota mechanics discount as "the" root cause of engine problems. Maybe it was good that engine repairs were not started in August considering the high voltage issues now.
     
    #4 rjparker, Oct 4, 2021
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  5. tankyuong

    tankyuong Senior Member

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    New car
     
    #5 tankyuong, Oct 4, 2021
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