Red Triangle Light On, Thinking its the Inverter Coolant Pump

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by vskid3, Aug 7, 2015.

  1. vskid3

    vskid3 Active Member

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    While driving on the freeway today, the red triangle and check engine lights lit up and a message saying "Problem" appeared at the top of the MFD. My Ultragauge didn't show anything out of the ordinary (doesn't show inverter temp or other hybrid specific gauges) and a Google search of the code it found, P0K93, didn't find any results, so I drove about 8 more miles to get home (my wife was doing the Googling, not me). I found another thread where someone had gotten a P0K92 code. Apparently neither of them are valid codes and are caused by a non-Prius-aware scanner not understanding the Prius codes. I've ordered a mini-vci cable and it should be here by Monday.

    The other thread ended up being a MG1 failure, but nothing points to that be the case for my car. I decided to start with the basics and check the inverter reservoir for turbulence. It looks completely still. P0A93 is the code that should show up if there's something up with the inverter cooling system, so I'm thinking the P0K93 will end up being a P0A93 when I scan it with Techstream.

    Does my initial diagnosis seem correct? Is the turbulence in the inverter coolant reasonably noticeable? I removed the cap and waited for the ICE to stop and it looks still as can be to me. Is the recall for the inverter pump still valid?


    Also, possibly unrelated, last night, the AC stopped working. The air coming out of the vents started gradually getting warmer. I figured it had just cooled down to the temp I had it set at, but even turning it down to max cold was still the same as just the vent with no AC. I went out to try it again about 30 minutes after getting home and it was blowing ice cubes as usual. Blew nice and cold again today.
     
  2. bisco

    bisco cookie crumbler

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    you should definitely see swirling with the car in ready and the cap off.
     
  3. JimN

    JimN Let the games begin!

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    Run the VIN at Toyota Owners Official Web Site to see if the inverter coolant pump is covered. Just calling the dealer may or may not get you a correct answer depending on how hard that person looks.

    Is your gauge capable of reading the inverter temp or the coolant temps?

    Until the inverter coolant pump is replaced I would keep driving to an absolute minimum and only in the coolest parts of the day. When the inverter gets too hot it will shut down and you will be calling for a tow from the side of the road.
     
  4. jadziasman

    jadziasman Prius owner emeritus

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    With a P0A93 code, it almost certainly is the HV inverter electric coolant pump which failed. Mine failed at 185K miles. Have driven more than 50K miles since it was.

    Not sure if the limited service campaign is still active. Mine was replaced three years ago. Either way, it won't cost you much to replace it if you DIY. The part is less than $200.

    Don't drive it that way. Replace it ASAP.
     
  5. vskid3

    vskid3 Active Member

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    On the Toyota Owners site, it shows up as good on safety recalls. The maintenance record shows that a factory recall was done in July 2011. I could have sworn I'd seen something about the inverter pump being replaced when I'd checked that site in the past, but it looks like I was imagining things.

    I'm not planning on driving it until I get the mini-vci so I can at least monitor the temps. Unfortunately, while the Ultragauge is better than the Scangauge II for day to day use (in my opinion), it can't do any of the hybrid x-gauges like the Scangauge, just the standard OBD-II gauges. I'll probably just drive it to the dealer when I can and check if the pump is covered under a recall and if there are any others that need done.
     
  6. ChapmanF

    ChapmanF Senior Member

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    I'm wondering, have the inverter coolant reservoirs stopped being see-through on the newer Prii? I keep seeing posts about "take the cap off and look for swirling" when it used to be so easy ... on a Classic the return hose comes into the front of the reservoir, and you can just glance at the reservoir and see the fluid level is higher in front when the pump runs.

    -Chap
     
  7. JimN

    JimN Let the games begin!

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    The fluid containers are milky white plastic.
     
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  8. vskid3

    vskid3 Active Member

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  9. bisco

    bisco cookie crumbler

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    can you get there under 20 mph in 50 degree weather?:p
     
  10. vskid3

    vskid3 Active Member

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    It'll be a few months before we see 50F here. ;)

    Went to the dealer in my truck and had them check the VIN. Turns out the recall work done in 2011 was the inverter pump and the recall only covers one. :eek: The pump itself is about $150, they'd want another $150-200 for coolant and labor. I'll probably just do it myself, doesn't look bad.
     
  11. bisco

    bisco cookie crumbler

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    haven't done it myself, but most here say it's pretty simple. bleeding seems to be the laborious part.
     
  12. vskid3

    vskid3 Active Member

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    Swapped out the pump today. Followed Hobbit's advice and removed the headlight to allow easier access. I also didn't want to drain all the coolant, so I clamped off the hoses with a pair of these. Lost maybe 1/4 cup of coolant doing it this way.

    Thanks for the help, everyone!

    Wide open spaces.
    [​IMG]

    Clamp locations.
    [​IMG]

    Coolant lost, most of the sediment was already in the container and the rest was washed from the side of the pump as it leaked out.
    [​IMG]
     
    #12 vskid3, Aug 22, 2015
    Last edited: Aug 22, 2015
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  13. jacobprius2010

    jacobprius2010 New Member

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    I am unsure where to post this as I am new to the forum/website. However, about 2 months ago I drove to a store, spent about 2 hours there, and then when I came back it had all sorts of messages on my 2010 Toyota Prius. Mainly, it said check parking system as it is on uneven surface.. .. not quite that language but something about this. I took it to my local dealer and they said the ECU had been fried, my 12v battery was dead and not working, and a fuse had been blown. Ultimately, I had my 12v battery replaced (I had replaced it a year earlier and had a warranty on it yet), replaced my ECU, and replaced the blown fuse.

    Then less than one month later I had a "check hybrid system" light come on along with the bright orange triangle caution light, and the check engine light. Ultimately, I took it to the same dealer who said a code P261B came up and a different code regarding my intake engine manifold. The dealer said I needed a new engine water coolant pump and recommended I replace the engine manifold because, as they said, it cannot be cleaned but only replaced. Yesterday, I spent about $800 to replace the electric engine water coolant pump. I did not do the intake engine manifold because that was going to cost another $600, which I do not have. I picked up my car today, no check hybrid system light nor any check engine light. I drive approximately 20 miles and then later tonight the check hybrid system" light come on along with the bright orange triangle caution light, and the check engine light all reappear.

    When I got home and parked my car I looked inside my hood and saw my engine inverter coolant level was right at the low level. Could this low level engine inverter coolant cause all of these lights? If not, any recommendations or suggestions? I am, obviously, taking my car back to the dealer tomorrow. This is turning into a three month, >$1,600 ordeal so any help would be appreciated!
     
  14. JimN

    JimN Let the games begin!

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    Jacob, it sounds like you have/are experiencing unrelated problems. My first suspect is a leaking or inoperative inverter coolant pump. If the pump is leaking it will be inoperative. Perhaps you just have a bad hose. Was the recall to flash the ECU performed?

    Since you have lights ask for and post the codes behind them before authorizing any work.
     
  15. jacobprius2010

    jacobprius2010 New Member

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    When the ECU was replaced they performed an update to the ECU which took approximately 6 hours, they said. I would assume that was the flash you are referring to. I had my engine coolant pump replaced, but is that different than the inverter coolant pump? My car still runs, though after a certain amount of miles the check hybrid system lights appear. I would have thought they would check the bad hose before changing the engine coolant pump. Further, I did notice yesterday, both before starting the car and after immediately running the car, that the inverter coolant level was right at the "L" mark. Today they informed me that the main code is P261C for my Toyota Prius 2010, and they are talking to Toyota uppers tomorrow because they "have 48 pages worth of information" and are hoping to have Toyota put forth some work...aka they don't know what is going on. It is a reputable Toyota certified dealership I am taking it to.
     
  16. exstudent

    exstudent Senior Member

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    Yes.
     
  17. Brodgah

    Brodgah New Member

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    Car on and would you see the coolant liquid dramatically swirling or just moving?
     
  18. bisco

    bisco cookie crumbler

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    moving.
     
  19. Brodgah

    Brodgah New Member

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    When turning the car on I can't really see movement but the motor is on so it's kind of moving the liquid.. should it be noticeable that it's moving or should you have to squint to see it?
     
  20. ChapmanF

    ChapmanF Senior Member

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    I remember in the Gen 1 reservoir there was a little plastic baffle (don't know if Gen 2 is the same way), so that you could plainly see, just by looking through the milky plastic bottle, that when the pump was running the coolant level in the front of the bottle was about a cm higher than the level in the back. Seemed easier than trying to make judgments between moving and swirling. :)

    -Chap
     
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