2008 getting P0a93 after inverter pump replacement

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jewellrunner, Jul 20, 2020.

  1. jewellrunner

    jewellrunner New Member

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    First post here. I tried to search for something similar but haven't found anything quite like this. I bought a 2008 Prius a few weeks ago. The dealer specifically told me he had just replaced the inverter coolant pump. Well, 2 days later the red triangle, VSC, check engine lights came on while driving on the highway. (Also of significance, it's been sunny and in the 90s here recently.) Took it to the place I bought it and he scanned P0a93. First thing he tried was clearing air from the lines. Again, he told me he had just replaced the pump so he thought the air was probably the issue. The next time I took it on the highway, lights on again almost instantly. I took it to my trusted mechanic and he confirmed that the pump was new but diagnosed that the pump might be faulty and to ask the dealer if the part was under warranty. I took it back to the dealer and he replaced the pump. He also kept it and drove it about 50 miles to ensure it was good. After I got it back, I also made it about 50 miles but eventually the lights came back on.

    Literally the only thing I can find is an old reddit thread:

    I haven't take any temps like he has but otherwise the description of the problem is very similar.

    Anyway, the car is with the dealer again. He called today to say he replaced the inverter itself and it going to test drive again and I can pick it up tomorrow. Unfortunately, it's a cloudy and cooler day so I don't know if it will trip the code even if there was still a problem.

    So, my two main questions: 1) Does it sound reasonable that he replaced the entire inverter? My understanding is that it's very expensive and he's doing this at no cost to me. His reviews are fantastic so I'm not surprised he's protecting his reputation but that seems like a lot to do for a good review. I'm a little worried he's just trying to get rid of me. 2) Should I just go forward and hope for the best or should I get it back to my mechanic or a Toyota dealer for further diagnosis after all this?

    Thanks!
     
  2. TMR-JWAP

    TMR-JWAP Senior Member

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    Replacement inverters are cheap and just a couple hours of work to R&R... There's plenty of salvage vehicles available. I have 3 Gen 2 inverters in the shop as 'just in case' items. I think it's great the guy is taking care of the problem (hopefully)....reputation is everything..
     
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  3. jewellrunner

    jewellrunner New Member

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    Oh cool, good to know. Guess the best I can do is wait and see if the lights come on again. If so, I'll probably go straight to a Toyota dealership and figure it out once and for all.
     
  4. jewellrunner

    jewellrunner New Member

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    He just called and said the inverter replacement did not work (lights back on, code still being thrown). He took it to a Toyota dealership for them to diagnose. Really interested to hear what they say is the problem.
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    P0A93 can be things other than the pump, tho. It has two possible subcodes. 346 and 347.

    346 designates it as a likely cooling water pump system problem
    347 designates it as a likely cooling fan circuit problem.

    But of course, either one may be triggered by any of the combined causes, including the inverter.

    Hope they get it solved for you.
     
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  6. jewellrunner

    jewellrunner New Member

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    Hmm, not sure he's looked into the cooling fan circuit at all. At this point, I have the car back and it triggered the lights on the highway yet again so I'm taking it to the Toyota service dept myself to get a diagnosis I can trust once and for all. (There's a language barrier between me and the dealer, so I'm not 100% certain he took the car to a Toyota service dept despite him saying he was going to.)

    I'm guessing those subcodes only show when using Techstream?
     
  7. Thomas Wesley Heard

    Thomas Wesley Heard New Member

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    What can be done to solve the circuit fan cooling problem? Just had my coolant inverter replaced.
     
  8. dolj

    dolj Senior Member

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    @jewellrunner and @Thomas Wesley Heard, referring back to the OP, it could also be a blockage in the inverter cooling fins inside the inverter. Less likely for jewellrunner as the whole inverter was replaced, but it is feasible the replacement inverter was clogged as well (maybe the reason it was changed out). Blockages are most often the reaction caused by mixing and matching different coolant formulations – even if they are the same color even! If you (not necessarily directed at the posters) are using a different brand of coolant, drain the entire loop and flush, before installing a new brand of coolant.

    It would pay to eliminate a blockage as a cause though.

    Another poster here had a clogged inverter and manage to unclog it enough using water pressure from a water hose (in both directions alternately) to get the system to stop throwing the P0A93. He reported a gritty black sludge coming out.

    Just a thought.
     
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  9. dolj

    dolj Senior Member

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    Attached Files:

    #9 dolj, Jul 31, 2020
    Last edited: Aug 1, 2020
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  10. Thomas Wesley Heard

    Thomas Wesley Heard New Member

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    How can I tell when the code pops up if its /346 or /347? Does the OBII say?
     
  11. Raytheeagle

    Raytheeagle Senior Member

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    Those are information codes that display to help with further troubleshooting and narrowing the cause;).

    Techstream will have them and some more advanced readers might (like an Autel):).

    Good luck and keep us posted (y).
     
  12. edthefox5

    edthefox5 Senior Member

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    You can check pump and circulation just open the cap of the inverter reservoir look inside at the coolant should look like it’s boiling meaning aggressive pump action. If it’s tepid movement or just sitting there you either have an airlock Or new pump is not a denso pump or the inverter aluminum cooling channels are clogged. Pump could be dead to as when the previous pump failed it ususlly blows fuse am2. If the nverter system has an airlock you may be able to hear the pump making noise as it circulates airlock.

    Get an Ir thermometer and do some tests a happy inverter coolant system should be 70-80 degrees cooler than the engine.

    Also since the inverter coolant shares the rad make sure the rad is full and engine not running hot.

    Take black plastic cover off the top of the rad take the rad cap off coolant should be right to the top of the cap. If rad low you may have a leak check fir engine water pump leak. Neither the op or the hijacker could post there mileage.
     
  13. Thomas Wesley Heard

    Thomas Wesley Heard New Member

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    The readings I got

    Car Scanner ELM OBD2
    DTC report
    Selected brand: Toyota
    VIN: JTDKB20U473265191

    ============1==============
    P0A93
    Raw code: 0A93
    ECU: 7EA
    Status: Confirmed
    OBDII: Inverter A - cooling system performance
    ============2==============
    P0A93
    Raw code: 0A93
    ECU: 7EA
    Status: Pending
    OBDII: Inverter A - cooling system performance
    ============3==============
    P0A93
    Raw code: 0A93
    ECU: 7EA
    Status: Confirmed
    OBDII: Inverter A - cooling system performance
     
  14. dolj

    dolj Senior Member

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    If you have a good scanner you should be able to drill down into the freeze frame data which is where you will find the sub-codes (aka detail codes or INF codes). If you can't get to the freeze frame you will just need to check both. Looking at the pump first and verify that is working and you see vigorous movement in the inverter coolant reservoir. If that looks ok, move on to the diagnostics for the fan and cooling radiator.
     
    #14 dolj, Aug 2, 2020
    Last edited: Aug 2, 2020
  15. Thomas Wesley Heard

    Thomas Wesley Heard New Member

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    Today I drove about an hour in hot weather (90 f) and I had the heater on the whole time
    No codes popped up
    Does this mean anything? Other than something’s overheating
     
  16. dolj

    dolj Senior Member

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    Yikes! Or do you mean the climate control cooling you? If you did indeed have the heater on, was it blowing nice and hot?
    It could mean you did have some air in your system but it has now shifted and no longer air-locked. You could verify this by checking the level in the inverter reservoir. If this happened, the level would be lower and it may need a top-up.
    Not sure I understand your meaning. Why would you think something's overheating if there are no codes?
     
    #16 dolj, Aug 4, 2020
    Last edited: Aug 4, 2020
  17. Thomas Wesley Heard

    Thomas Wesley Heard New Member

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    I’ve gotten the p0a93 code every time I’ve driven in the heat, which is at least 90 f, every time. Tried blasting the heat yesterday and it didn’t set the codes. and yes heater was nice and hot.
     
  18. edthefox5

    edthefox5 Senior Member

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    What does the car's heater have to do with the inverter pump issue? The cars heater heat is coming from the engines radiatorr just like any other car.

    The inverter cooling system is completely separate its designed to cool the inverter and the trans. has nothing to do with cabin heat..

    Please read my earlier post and do what I suggested. takes 5 seconds to do. look at the inverter coolant in its reservoir. i bet its just sitting there not moving when the car is in ready. Pump fuse AM2 is probably blown.One of the most common prooblems on a prius there is.
     
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