1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Replaced 12V batt. & coolant inverter pump replaced 14 mos ago - still no coolant circulation

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SeattlePriusowner, Oct 26, 2024.

  1. SeattlePriusowner

    SeattlePriusowner New Member

    Joined:
    Oct 25, 2024
    5
    0
    0
    Location:
    Seattle
    Vehicle:
    2007 Prius
    Model:
    N/A
    I have a 2007 Prius with 124K miles. When I run it in IG-ON mode, the pink fluid in the inverter coolant reservoir is not gently swirling around. Worried that this will eventually cause my inverter to fail.

    Was driving a month ago and on my dash I had the Master Warning alert (red ! triangle), VSC light and yellow brake warning light (yellow ! inside circle, inside parenthesis) all come on at the same time. Also, on the LCD touchscreen, the icon of the red car with ! came on. When I got home, I used my OBDII scanner on the car and it threw 3 codes: P0A93 (inverter cooling system performance), P2601 (coolant pump control circuit rang/performance) and P0420 (catalyst system efficiency below threshold Bank 1 -- it's thrown this before and I think it's just from putting in an aftermarket CC in after mine got stolen a few years ago).

    Went on this forum to see things I could do to troubleshoot. Put Prius in IG-ON mode and observed that the pink fluid in inverter coolant reservoir is not gently swirling. I already had the inverter coolant pump, engine water pump and water control valve replaced 14 months ago along with a coolant flush (at a local shop not specializing in hybrid vehicles; I know to go to a specialized hybrid shop next time). I called the shop that did the work; they said another one of their customers having the same problem -- had the pumps replaced recently, but fluid in inverter coolant reservoir is not gently swirling in IG-ON mode. Shop said that customer took their Prius to Toyota dealership and they fixed the problem -- something having to do with the electrical solenoid not sending power properly to the inverter coolant pump. The dealership said it would cost me $200+ tax for them to do diagnostics.

    I called a hybrid shop and they suggested that Auto Zone read the 12V battery capacity. They measured it at just 66% State of Charge ("failed") so we had them put a new 12V battery in. After they did that, the red triangle dash light did go away, but when I run car in IG-ON mode, the fluid in the inverter coolant reservoir is *still* not moving and I don't hear any pump sound. I hooked up my OBDII scanner a couple of times since the new 12V was put in, but no codes are being thrown. The car drives fine, but I'm trying to not drive it much these days because the inverter was very hot to the touch when I drove it (warning lights came on again suddenly) before replacing the 12V.

    What should I try now??

    Also, adding this because it might have to do with battery system problems: I was rear-ended 3 months ago, and it's possible that some connection came loose when that happened.

    Thanks in advance!
     
    #1 SeattlePriusowner, Oct 26, 2024
    Last edited: Oct 26, 2024
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,273
    1,774
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    So now put the car in ready mode in park hood release lift the hood and get out and put your hand on the inverter pump while the car is sitting there ready running good to go Do you feel the inverter pump vibrating If yes maybe the reason it's not moving any fluid is because it's not full enough are you on the full mark on the inverter coolant reservoir? If you feel vibration and it's full and there's no movement then more than likely they put on a cheap inverter pump and they last about 90 days maybe 120 to 180 if you're lucky now get the real deal the Toyota pump and you probably won't deal with it for about 8 to 10 years You live and learn I guess I would be very surprised if the shop put on 130 plus dollar real Toyota pump and it's failed again highly unlikely but it is possible.
     
    SeattlePriusowner and Brian1954 like this.
  3. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    11,318
    4,610
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    I live near you in Olympia... You have nothing to worry about. The inverter has a thermal shutoff when it gets too hot to protect it from damage. When you have a bad inverter pump, the red triangle is that shut down. And in our part of the country, if you're only driving locally, the next time your inverter will get too hot and shut down is next May when weather finally heats up.

    And if you're ever in town and want an inverter pump I've gotten real fast at doing them because I prefer the $27 pumps over the $150 OEM pumps for my friends and me.
     
    SeattlePriusowner likes this.
  4. SeattlePriusowner

    SeattlePriusowner New Member

    Joined:
    Oct 25, 2024
    5
    0
    0
    Location:
    Seattle
    Vehicle:
    2007 Prius
    Model:
    N/A
    Thanks so much for your reply! Yes, it looks like the pink fluid in the reservoir is right around the full mark.

    It seems like the inverter pump itself is far down under the easily accessible top portion of what's under the hood -- are you asking me to reach way down and try to touch the inverter coolant pump, or just to touch the big silver hood that encases the actual inverter?
     
  5. SeattlePriusowner

    SeattlePriusowner New Member

    Joined:
    Oct 25, 2024
    5
    0
    0
    Location:
    Seattle
    Vehicle:
    2007 Prius
    Model:
    N/A
    Thanks very much for the info, and the offer! I drove the Prius a little bit today, and it operated fine, with no error lights coming on on the dashboard. There was a weird sound coming from under the hood intermittently, though (please see my update comment from today in this same thread).

    Even though it's great that the weather isn't very warm these days, I'm still nervous about driving a car that I am almost positive has an inverter pump that's not running (as evidenced by me not seeing any fluid movement in the inverter coolant reservoir when the car is in IG-ON mode). I would hate to have to buy a new inverter because that pump isn't working and isn't keeping the inverter cooled down.
     
  6. SeattlePriusowner

    SeattlePriusowner New Member

    Joined:
    Oct 25, 2024
    5
    0
    0
    Location:
    Seattle
    Vehicle:
    2007 Prius
    Model:
    N/A
    I have a new piece of information.

    Today was not a hot day and I drove the Prius a short distance for a couple of errands. A few different times, I could hear a sound coming from under the hood, roughly in the area where I know the inverter coolant pump is. It sounded like a machine or pump rapidly making sounds at a quick and steady cadence; the sound wasn't quite an electronic sound, but more of a mechanical sound, like a pump loudly trying to push fluid through a pipe. I think it might be the inverter pump struggling to work. The sound would happen for about 10 or 15 seconds, then stop, and then the same sound would happen again, maybe after I started the car up again. I didn't get a chance to pull over, put the car in park, and check under the hood to see if I could find what part was making the sound.

    There weren't any error lights on my dashboard while I was driving today. I never drove more than about 40 mph.

    Anyways, that's the update.
     
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,273
    1,774
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Right behind the headlight is your inverter pump You can reach your hand down there unless it's as big as King Kongs your hand that is and just put it on top of the inverter pump while the car is ready running sitting there in park You should feel the inverter pump moving vibrating then you can squeeze either of the hoses that you're right there with your hand on top of squeeze it like you're milking a cow Do you feel the fluid moving or bubbling or anything like that in the hose while the pump is running? There is a bleed screw on front of the silver top inverter You can crack that bleed screw and water should come pumping right out remember to close it
     
  8. pasadena_commut

    pasadena_commut Senior Member

    Joined:
    May 2, 2019
    1,696
    512
    0
    Location:
    Southern California
    Vehicle:
    2007 Prius
    Model:
    N/A
    That is going to make a bit of a mess if the pump is working. Maybe attach a piece of tubing to the bleed screw first and run the other end into the inverter coolant tank. Fluid might come out of the bleeder due to gravity if the car isn't level even if the pump isn't working. But it won't go up that tube all the way to the tank opening, as that will be higher than all the fluid in the loop.

    After closing that screw blot it dry then rinse it off thoroughly with some distilled water. Dried coolant makes pink crystals, and it is good to know if that indicates a leak from a not quite closed bleeder screw. If one leaves a mess then there is no way to know if the crystals are from that or a slow leak.
     
  9. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,273
    1,774
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    I just crack it ever so slightly with nothing on it My 10mm wrench controls the flow that lifts up out of that bleed screw I just watch it for a second it just comes up about old half inch above my wrench and drops down on the wrenches shank and then onto the plastic If I see no air and everything looks good I close it up take my Dasani bottle and pour that over my wrench and let it go down where the coolant spilled and it runs on the ground and off I go but yeah you wouldn't want to crank that thing wide open staring at it why would hit you in the face
     
  10. SeattlePriusowner

    SeattlePriusowner New Member

    Joined:
    Oct 25, 2024
    5
    0
    0
    Location:
    Seattle
    Vehicle:
    2007 Prius
    Model:
    N/A
    Sorry for the delay; been dealing with the trunk leaking due to the rear-end collision the car was in.

    I just tried putting the car in park, running, and felt the inverter pump itself and the hose that connects to it, to see if I could feel any vibration or movement of fluids. I couldn't feel any movement. I could intermittently hear a noise coming from the general area of the inverter pump -- a rhythmic sound that sounded like a motor trying to turn on but struggling. I think it's the same sound I described in my last post. I ran the OBD2 scanner and it gave me one code: P2601 (coolant pump control circuit range/performance), which it has thrown before.

    So it sounds like I probably just need to get the inverter coolant pump replaced. Would you guys agree?
     
  11. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,273
    1,774
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Yes if the car is ready in park you're standing outside of it your hand is on the inverter pump and it's two hoses one hand drops over everything and you feel no vibration obviously there's going to be no water movement and that's the end of that if the pump is vibrating and it's not cavitated meaning there's an air pocket that's all you'll hear is a vibration and you may feel the hose that's not in the center of the pump fluctuating very little if you grab that hose and wrap your whole hand around it it's only about a 5/8 outer diameter like a heater hose and then if you usually take the reservoir cap off you can see little ripples in the water like you see on the lake in the morning and that's about it it doesn't really have to be whizzing around the loop too quickly then it wouldn't cool properly.