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2017 Prius Prime - P0A93 Error

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by RaphaelCaesar, Aug 12, 2023.

  1. RaphaelCaesar

    RaphaelCaesar New Member

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    Hi all, I'm in great need of some expert Prius opinion here. I just got my first Prius 3 weeks ago - it's a 2017 Prius Prime with about 70k miles on it. I've been driving it for 3 weeks and loving it with no issues!

    However, today, I was driving in standstill interstate traffic on a relatively hot day (90F). I had noticed that the air conditioning was starting to put out some warmer air, so I cranked the settings all the way down to low with high fans to get things colder. The air was still warm but I noticed it started to get colder the faster we drove, and then would get warm again when things went back to being standstill.

    During the standstill traffic, I got 3 errors: 1)Hybrid System Malfunction. Reduced Output Power. Visit Your Dealer, 2) Pre-Collision System Malfunction. Visit Your Dealer, and 3) ICS Malfunction. Visit Your Dealer.

    I pulled over, but unfortunately we were only 30 minutes away from home. So after pulling over, taking a look (finding nothing), I drove the rest of the way home <55 mph. On the way, I stopped at Autozone and pulled my P0A93 error - Inverter Cooling System Performance. After doing some quick mechanic googling, I saw a few Prius forums recommending letting the car charge, turning off and on again, and then exploring other options.

    Well - I went back out to my car this evening to see how it looks and the errors did NOT come up again. I drove around the block, put it into power mode, and tried to see if any drive modes got error messages again.

    I'd like to see what the Prius experts think. I know the P0A93 code was common for Gen 2, but in all my researching I have seen very little about Gen 4. It seems like replacing the Inverter Cooling Pump is the normal fix. There's a lot of videos, forums, and comments about doing that very thing on Gen 2 and Gen 3, but again, I've had a hard time finding this for 2017s.

     
  2. bisco

    bisco cookie crumbler

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    in general, gen 4 is too new for many failing pumps. is there movement of the fluid in the reservoir?
     
  3. RaphaelCaesar

    RaphaelCaesar New Member

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    I tried to look, but I didn't see much. I drove around the block and then parked. I put it to the IG - ON mode and checked the coolant. I couldn't see any coolant moving but also I am not sure if I set it up correctly. Even with the IG - ON mode, the engine wasn't making any sound at all. It was completely quiet while stationary. So as far movement in the reservoir, I'd say not, but am not confident I did the test setup correctly
     
  4. bisco

    bisco cookie crumbler

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    you could put it in ready mode. the engine won't come on, and you can look for movement, it should be obvious.
    you can also check the AM2 fuse
    around one minute:

    search
     
  5. RaphaelCaesar

    RaphaelCaesar New Member

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    Gotcha. So basically as long as it's in ready mode with the trunk open, I should be able to see the turbulence? And if not, then it's probably safe to say it's a blown pump?
     
  6. bisco

    bisco cookie crumbler

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    correct, and the trunk does not need to be open
     
  7. BiomedO1

    BiomedO1 Senior Member

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    You should first check the electric cooling fans, mounted to your radiator. If they're not turning - you can't get rid of the heat generated. You stated that once you started moving again; everything began working again....

    Hope this helps....
     
  8. RaphaelCaesar

    RaphaelCaesar New Member

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    Thanks everybody for the suggestions. I've got an appointment with Toyota next week. In the mean time, feel free to let me know what you think of this sound! It came on while checking for the turbulence (didn't see any, likely confirming a bad pump)
     
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  9. bisco

    bisco cookie crumbler

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    could the active grille shutters be closed?

    what sound?
     
  10. BiomedO1

    BiomedO1 Senior Member

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    I found both electric cooling fans dead in a Honda CR-V I just bought. The previous owner stated that the AC was 'wonky' and sometimes blew warm air. He had it at the dealership twice and was quoted $5K+ for the repair. I've replaced entire AC systems on these models before and got it for a steal. Replaced both fans for $75 and it's running great in stop & go traffic w/AC on, in 100+ degrees weather.
     
  11. RaphaelCaesar

    RaphaelCaesar New Member

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    Sorry - couldn't post the link because my account is new. The raw video should be attached here.

    Is there a manual mechanic for the grill shutters? Or is that supposed to be automatic?
     
  12. bisco

    bisco cookie crumbler

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    they are automatic, but there have been issues
     
  13. RaphaelCaesar

    RaphaelCaesar New Member

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    https://imgur.io/tgIGeqV
    Now that my post history is long enough, this is the sound. From another forum, I think this is the AC compressor working.

    https://imgur.io/tgIGeqV

    In another weird update, I was taking a look at the wiring inside the engine, and noticed both plugs for the radiator fan were completely undone. This is super strange to me, maybe an oversight from dealer service? I ended up connected them both back in. I've only been able get one of the fans spinning again when I turn on the AC. Not sure if these cables being unplugged would potentially be the root of all the problems?
     
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  14. bisco

    bisco cookie crumbler

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    sounds like it. does come on and off with the a/c switch?

    the cables could very well be the problem. what kind of service did you have done?

    both fans should be working
     
  15. RaphaelCaesar

    RaphaelCaesar New Member

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    Yep. I didn't make that connection until read it elsewhere and sure enough of my AC comes on then that sound comes on and off respectively.

    The fans are odd. I've seen them both come on at different points during my troubleshooting, but 90% of the time it's just one of them spinning. I can't seem to find a common theme that gets both to go, but in another forum for an older model I saw a comment about only one spinning if the car is in eco mode (and temps are down), but both spinning if it's in normal.

    I haven't gotten it serviced yet, just trying to troubleshoot some things on my own until next week. I'm taking it in for diagnostics for the error code that came up.

    Lastly, even after plugging everything in, I'm seeing almost nothing in terms of turbulence in the inverter coolant tank. I thought for a second maybe the radiator fans being properly connected would fix the overheating, but I'm afraid maybe I've still got to replace the pump.
     
  16. RaphaelCaesar

    RaphaelCaesar New Member

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    https://photos.app.goo.gl/CRWQiSathhnMPhBj7

    Above is a video link with the car idling after a quick spin around the block.

    You can see one fan going and the other not so much. Towards the end there's a shot of the inverter coolant tank. It sort of looks like there's flow, but it also looks like it's just the vibration from the fan/AC
     
  17. bisco

    bisco cookie crumbler

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    it is possible that they have programmed the fans separately based on temp, idk.

    that looks like coolant movement to me. shut the a/c off to be sure. i think it should also work in 'ig on' mode.
     
  18. BiomedO1

    BiomedO1 Senior Member

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    If you want to isolate and test fan performance. Unplug them and connect jumper wires. That way you can touch them directly to your battery. That should tell you if you've got issue with either fan. I'm pretty sure both fans should be spinning with the AC on. That AC condenser runs the entire length of the radiator; so it doesn't make sense for only one fan to be turning.
    I recall some older Hondas' having a condenser on one side and a radiator on the other side - two separate electric fans. Only one fan turning makes sense, if the car was setup that way.

    Just my 2 cents.....
     
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