Inverter coolant pump-should run constantly?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by BCS-TX-Prius07, Mar 6, 2020.

  1. BCS-TX-Prius07

    BCS-TX-Prius07 Junior Member

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    Over the last 2 months. 07 base Prius which I drive for rideshare. 197,000 miles

    Incident #1. Late night and have a rider. Red triangle and TPMS light pop up. No change in driveability. Drop off rider a few minutes later, back out of driveway, and car refuses to go. Bring up the battery level on the MFD and it's pretty much at zero. Engine was not running. Pushed it to the side of the road while deciding on who to call for a tow. Powered down and powered back up. Engine starts and battery begins charging and TPMS light is gone. Drive home. Watch battery level which increases in a normal manner. Shut down at home and bed. Next morning power up and red triangle is gone. Code reader shows no codes.

    Incident #2. Couple of weeks later. Again late night and triangle and TPMS light up. Pull over and check battery level, which was at about half. Engine not running. Power off and back up and engine begins running and charging the battery. Drive home, power down, run reader, no codes. Power back up and all warning lights are gone. By now I keep the MFD showing battery level at all times.

    Incident #3. Pretty much the same as #2. Never can get a code but I do notice that at times the battery level is dropping while stopped for a period of time and the engine is not kicking on to charge. In Drive I give it some gas with my foot on the brake and the engine kicks on and charges.

    Incident #4. Same as before except I also get a Check Engine Light. Drive home and finally pull a P0A93 code. Inverter coolant pump.

    Should that pump be running at all times if the car is powered up? Because mine is not. Would this pump failure (if that's what it is) have any thing to do with the engine not coming on when the battery needs some charge?
     
    #1 BCS-TX-Prius07, Mar 6, 2020
  2. bisco

    bisco cookie crumbler

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    sounds like more than one problem. are you using tech stream?

    yes, the pump should run continuously. but it could be the pump, or a wiring problem
     
    #2 bisco, Mar 7, 2020
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    Odds are likely that you're experiencing high temperatures at the inverter due to the pump not running. That's probably what is throwing the triangle.

    If you keep your foot off the brake and pres the power button 2x, the car will be in Ig-on mode. The dash and mfd will be powered up and the pump should be running, but the car engine will stay off (not 'ready'). This will allow you to look in the reservoir to see if there's any flow ripples without engine vibration interfering. Then, if you put foot on brake and press power one more time, it should go ready mode. The pump should always be running in IG-ON or READY modes.

    As for the tpms, you may be confusing the warning lamp icons.
     
    #3 TMR-JWAP, Mar 7, 2020
  4. pasadena_commut

    pasadena_commut Senior Member

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    That said, I had a nonOEM replacement pump which failed to start intermittently, possibly the OEM pump has a failure mode like that too. Which isn't to suggest that is what you are seeing. The car can run an amazingly long time with the inverter pump not working at all before the car puts up any warnings. Especially if it is cold and you don't drive it on the highway. When the first (for me) OEM pump failed it just went totally - when out of the car and 12V was applied it wouldn't spin at all. You don't want to drive the car around like that for very long, even though it may not get hot enough to throw warnings, the inverter and transaxle will be running much hotter than normal.

    If you are at all handy with tools replacing the inverter pump is definitely something you can do yourself. There is a thread showing how:

    How to Replace the Inverter Coolant Pump | PriusChat
     
    #4 pasadena_commut, Mar 7, 2020
  5. BCS-TX-Prius07

    BCS-TX-Prius07 Junior Member

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    I followed the suggestion to put it into ignition mode only. Pump was not running nor was there flow in the reservoir. No flow with the engine running either. I'll tackle the pump replacement before trying to figure out if there is more than one problem. From what I've read here after market pumps are not the way to go. Correct?
     
    #5 BCS-TX-Prius07, Mar 7, 2020
  6. bisco

    bisco cookie crumbler

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    I believe that is correct
     
    #6 bisco, Mar 7, 2020
  7. M in KC

    M in KC Active Member

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    Yes buy an OE Toyota pump and SLLC if you plan to change the inverter coolant at the same time. A gallon of coolant ought to be plenty. Bleed the air out of the system after your repairs.
     
    #7 M in KC, Mar 9, 2020
  8. pasadena_commut

    pasadena_commut Senior Member

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    The first replacement I did was with one of these:

    Drive Motor Inverter Cooler Water Pump | 601-015 | Inverter Water Pump | Dorman Products

    and it soon developed the "sometimes does not start for any obvious reason" behavior. Working 99% (or whatever it was) of the time does not cut it in this application. Replaced it with an OEM and no issues since. That said, the Dorman might have just been defective, a sample size of one isn't very informative.

    I also suggest that after bleeding the air out of the loop that the bleed screw be cleaned really well and thoroughly dried after it is closed for the last time. Otherwise if pink crystals are seen on it later it could be either leaking (bad) or just residual coolant from the bleeding (no big deal). ( I did not do that on the first pump change and did see pink crystals when it was time for the 2nd one, but nothing since.)
     
    #8 pasadena_commut, Mar 9, 2020
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