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Dealership being vague about inverter problem

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by pirateyoho, May 30, 2017.

  1. pirateyoho

    pirateyoho Junior Member

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    Recently, I had my hybrid system warning light (along with the big red triangle, the (!), and VSC) come on for about a day on my 2005 Prius, and I made an appointment for maintenance at my local Toyota dealership to have it checked out. As luck would have it, the warning lights weren't on the day that I actually took it in, and they said they had a hard time digging up any codes that pointed them in the right direction, but the best answer they could give me was that my inverter was "starting to fail." (According to my bill, they pulled up POA08).

    I did a little bit of researching, and I'm just not very satisfied with their answer and I'm growing less confident that they looked very hard for the issue. From what I've gathered, a major reason that inverters fail is due to overheating, but he didn't specify if they checked the pump, the coolant channel, etc. All he said was that the cost of replacing the inverter would total my car, so I was better off just driving it until it failed for real, since my car still seems to be running normally.

    My warning lights have since all come back on, and for 2 days straight this time, but I'm wondering if it's really worth spending the diagnostic fee again to get another vague, unhelpful answer. Is there any value in going back with the warning lights on? Will that help them localize the issue? Is he right, and I should just continue to drive my car?

    Some additional info: I've checked my inverter fluid pump myself, and while there is some turbulence, I'm not sure how much is "normal" and if mine is still perhaps going bad. I know there was a recall a couple years back, but I didn't have mine checked out then, and punching in my VIN number on Toyota's recall website doesn't bring up any results. Again, I was hoping this was something that would have been checked when I went in, but I'm just not confident that that was the case.

    Even more info: car is at about 170,000 miles right now.

    Thanks in advance for any insight.
     
  2. andrewclaus

    andrewclaus Active Member

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    P0A80 is a failed hybrid battery. Until you have more codes supporting a failing inverter diagnosis, like a fault current code, there is no evidence of anything other than the bad battery. By the way, 12 years is a good long life for a chemical battery.

    I think there's no need to go back to the dealer for another diagnosis. The warning lights go out if the car sees a set number of "drive cycles" without an intermittent problem present. If the 12V battery wasn't disconnected or codes cleared by a scanner, they would remain in memory for the dealer to read. If they only read the battery code, they're guessing about other problems.

    If you saw turbulence in the inverter reservoir, the pump is working.

    The battery is an expensive fix. But if the car is otherwise sound and you like it, the new battery will probably last another 12 years. And it will be easily transferable to another Gen2 Prius.
     
    AliPK likes this.
  3. pirateyoho

    pirateyoho Junior Member

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    So if it is a failed battery, am I safe to still be driving it? Right now, it drives normally from what both I and the mechanics at the dealership who drove it a while could tell. I've been limiting myself to short trips to commute to classes everyday, but I had a 5-hour drive planned to visit the SO next weekend, and I'm wondering if it's unwise to think it will make the trip.

    Also, the code they pulled up was P0A08, not P0A80.
     
  4. andrewclaus

    andrewclaus Active Member

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    Oops, sorry for the confusion with the typo. I meant P0A08.

    If the warning lights are not staying on, the problem is probably intermittent. The code usually comes from a battery block value out of range, and it may pop up during heavy acceleration. It's also possible there are codes the dealer isn't reporting to you.

    It's hard to predict the future, but the lights are telling you something, especially the big red triangle. The best thing would be not to drive it. Most failures seem to be "soft," where you can limp off the road and there's no life safety issue. But it can be very inconvenient and costly.

    By the way, how is your 12 V battery? Do you know its age? There are easy ways to check some parameters if you do a search here.

    Do you ever notice fan noise coming from the back seat area? And do you ever notice the state of charge display, and is it fluctuating more than normal?
     
    Tim Jones likes this.
  5. pirateyoho

    pirateyoho Junior Member

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    I just had my 12 V battery replaced a couple months ago by this same dealer and haven't had any issues prior to this point. The state of charge has not been fluctuating, and I have not noticed the fan by the back seat come on. That used to happen a lot years ago, but it's been some time.

    I did get rear ended a couple of weeks ago; not sure if that could have knocked something loose on the 12 V batter since it's back there? But the symptoms seem awfully delayed, if that's the case.
     
    #5 pirateyoho, May 31, 2017
    Last edited: May 31, 2017
  6. pirateyoho

    pirateyoho Junior Member

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  7. bisco

    bisco cookie crumbler

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    certainly worth having a look back there. make sure the connections are clean and tight, especially negative to body ground.
     
  8. pirateyoho

    pirateyoho Junior Member

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    Could you direct me to a source where I might find out how to do that? Does it require accessing the 12V battery in the back of the car, or just inspecting the terminals under the hood?
     
  9. bisco

    bisco cookie crumbler

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    the back of the car. just google 'changing prius 12v battery' there should be plenty of you tubes showing where it is, how to remove all the cables, etc. you can the check for cleanliness and tightness.
     
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  10. andrewclaus

    andrewclaus Active Member

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    Given the minor collision, it's definitely a great idea to check the battery connections in back. As long as you're not removing the battery, it should be very easy. I don't think a problem there would give only that one code, but it's an easy thing to check and eliminate.

    Edit: Removed an incorrect statement due to mistyping the code.
     
    #10 andrewclaus, May 31, 2017
    Last edited: May 31, 2017
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. DTC P0A08 is indicative of a failed DC/DC converter within the inverter. It also could result from a failed DC/DC fusible link which usually happens only if the car was subject to a botched jumpstart.
    2. Make the Prius READY and measure the voltage across the 12V battery using a digital voltmeter. If the voltage is around 13.8VDC then the DC/DC converter in the inverter, as well as the DC/DC fusible link, are both fine. If the voltage is substantially lower then look for the fusible links within the main relay/fuse box, located in a 5" long plastic box with a clear cover. If those links are OK then the inverter probably needs to be replaced.
    3. You can buy a used inverter for $300 or so on eBay. If you can figure out how to install it yourself you will save very big $$$ compared to relying upon Toyota dealer service.
    4. If you decide to DIY the replacement, subscribe to techinfo.toyota.com to obtain factory repair manual info.
     
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  12. pirateyoho

    pirateyoho Junior Member

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    Thanks. The voltage readings were normal. Is a failing inverter something that could be intermittent, causing the voltage to look normal depending on when I happened to measure it? I just want to make sure I can safely rule it out with one reading, or if I need to take multiple readings to be confident that it's not the inverter itself.
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Bring your voltmeter with you. Next time the warning lights turn on, at that time leave the Prius READY and measure voltage across the 12V battery.
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    #14 Patrick Wong, Jun 1, 2017
    Last edited: Jun 1, 2017
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    #15 Patrick Wong, Jun 1, 2017
    Last edited: Jun 1, 2017
  16. edthefox5

    edthefox5 Senior Member

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    Go to lusciousgarage.com. They are a premier world clas Prius service center in San Francisco and search there repair blogs. They discuss that code in depth and how many a dealer has replaced the inverter and it not being the problem
     
  17. ericbecky

    ericbecky Hybrid Battery Hero

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  18. pirateyoho

    pirateyoho Junior Member

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    Would a bad 12V battery also cause the charging system warning light to come on? That has recently been added to my fun sporadic warning lights. The strange thing is that my regenerative braking seems to be working fine, and the HV battery seems to be charging fine as well, according to the master display. What else in the charging system could cause that light to come on, in addition to the others? Could the dealer be right about the inverter failing, then?
     
  19. edthefox5

    edthefox5 Senior Member

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    See post #13.
     
  20. pirateyoho

    pirateyoho Junior Member

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    Voltmeter reading at READY with the warning lights on was 11.9 V, if I recall correctly from this morning when I checked. Definitely below 12 V, though. It jumped to 13.7 V once the car was totally running.
     
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