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ZE3 Warranty - Error Code P0A94 - Recommendations?

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by legoadan, May 28, 2024.

  1. legoadan

    legoadan Member

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    Hi y'all!

    Short version:
    My car threw up the P0A94 error code. It's no longer throwing it up, however. I am going to take it to the shop to get it checked out. If the code came and went does that mean that the part is actually okay? Does anyone know if ZE3 warranty covers 2014 Prius Cs?

    Long version:
    Friday before a road trip I turn on the car for 5 minutes to let it warm up. It's 70 degrees outside. ICE turns on and after a cycle turns back off. No error codes. I have to pack some more stuff so I turn the car off and pack.

    Then, 15 minutes later, we're ready to go. I turn on the car and all is good. We drive for 30 seconds. I hit a very rough patch of road and immediately I get the dreaded "CHECK HYBRID SYSTEM STOP THE VEHICLE IN A SAFE PLACE IMMEDIATLY" AND the car starts beeping at me aggressively.

    I stop the car. Wait 60 seconds. Turn the car back on and the message is still there BUT the car is not beeping at me. The car feels like normal. Electric engine and ICE feel correct and there is no loss of power. I drive a little more. After 2 minutes in the ICE turns off and will not turn on. The car starts beeping like crazy. I think we're in limp mode as I can't get over 40 MPH.

    We stop the car and turn it off. We wait and turn back on. Error still there. Aggressive beeping stopped. ICE turns on like usual. We drive surface streets in case the car wants to go into limp mode. We stop by an AutoZone and they give us a free code check and we get P0A94 - Inverter. We get to my parents and swap cars with them.

    After 5 minutes of chit chat with my parents, we have to move my car again. We turn it on and the error code is gone!! We still have our road trip and we don't want to risk it so we take another car anyway.

    Saturday and Sunday pass. Monday comes and we return from our trip. We swap cars again and the error message does not pop up at all. Car feels normal. Tuesday (today) I drive the car and it feels like normal and has no error code.

    Ask:
    I am trying to figure out what to do. I checked the forum and found things about the same error code and ZE3 warranty, but it seems like that's only for regular Prius (not the C or V). I am unsure about that. I know that I might be able to do the repair myself, which I might do if the dealer tells me that the part is not covered and the repair is too expensive with them. The error did only pop up when I hit a bump so I am wondering if the error is legit. I did also just get a new lithium battery so I wonder if that could mess things up.

    Thanks!
     
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Does not apply to the c.

    Don't assume anything is broken or burnt out yet. The best thing you can do is get a thorough diagnosis from a scan tool. You may or may not get that from autozone, I don't know what tool they use.

    The Prius is pretty picky about scan tools, because it has several different computers on board and they use different languages. So you need a scan tool that speaks all of them.

    If you are interested in any DIY work I strongly suggest getting your own setup. Toyota Techstream software on a windows laptop with a USB-connected J2534 interface is a great way to go. There are also bluetooth-enabled OBD interfaces and smartphone and tablet apps that work well.

    I recently invested in an Autel AP2500E setup for my phone, and it was of great help in diagnosing a problem in our car, and then later clearing the codes once the problem parts had been changed. I spent under $70 for that tool.

    Meanwhile-

    Have you popped the hood and looked at the inverter coolant level?
     
    legoadan likes this.
  3. legoadan

    legoadan Member

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    I will definitely be looking into this. Thanks for the suggestion.

    No, that's a good suggestion too! After work I'll see if I can figure out how to check that.
     
  4. legoadan

    legoadan Member

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    Looks a little low, but nothing dangerous. It's right above the "low" line I think (though the car is parked on a slight slope).

    [​IMG]
     
  5. Sonic_TH

    Sonic_TH Active Member

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    When the car is on, can you feel the inverter coolant pump vibrating? it's right in front of the inverter, put your hand on it to see if it is vibrating.
     
  6. legoadan

    legoadan Member

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    Sorry for the delay. I often forget to check back on the forums. I did check the pump and it seemed to be working. I also asked a tech to look at it and they said it was fine. So I'm leaning towards ruling that out.

    Also, an update on the inverter failure since I last posted:

    After 135k of the stock inverter, and after switching to Lithium at 130k, the inverter failed. I posted on this thread. Then, I swapped to a used inverter for $995. That included the inverter part, install costs, and coolant drain and refill for the inverter. The new piece came with a 90 day warranty. I drove around 2k and now the piece is showing up the error again.

    I'm not sure if the problem is the inverter or really the new lihium battery. One thing I've noticed is that BOTH times the part failed it failed immediately after I hit a really rough patch of road. It seems like my issue is triggered by pot holes?!?

    Today, I turned on the car and the error is no longer showing. I know it's saved and I plan on taking the car to the mechanic to use the warranty. I just find it odd that the shaking/jolting/vibrating/shock of hitting a pot hole is causing the error and I sort of suspect that my problem isn't with the part—instead, it might just be a false positive from the sensor. Each time the part has "failed" the car runs find after and runs without the check engine light or the "stop the car" screen.

    Has anyone else had experience with their car showing an inverter failure after hitting a bump? Has anyone had similar problem with their inverter after installing a ithium battery?
     
  7. Sonic_TH

    Sonic_TH Active Member

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    That's weird, i do not think that the bump caused the inverter failure, do you still have your old inverter? Also, do you have an OBD2 scanner? if you do, download Dr. Prius and connect it to the scanner, take a look at the voltage difference of the modules in the hybrid battery while the state of charge goes down, if the voltage difference shows 1.2 v i think, then there is a module i the hybrid battery that is going bad, or multiple modules.
     
  8. legoadan

    legoadan Member

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    Just bought this doohickey. It has Wi-Fi so I'm hoping I can use the Toyota Techstream with it. I bought it because it was recommended on the Dr. Prius list of scanners. I'm really excited to see the battery level of each cell, lol.
     
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  9. Sonic_TH

    Sonic_TH Active Member

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    Good, update later on what you find with the scanner
     
  10. Brian1954

    Brian1954 Active Member

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    The NEXAS Netlink OBD2 doggle does not operate by WiFi. It operates by Bluetooth. It will not work with Techstream but should work with the Dr.Prius app.