The engine water pump was leaking and I replaced it along with the drive belt. I burped the system with the help of using the relay for the heater pump. All went well BUT in the last couple of days, I get intermittent red triangle and the red thermometer on the MFD. NO codes. The car will not let me drive it above 40 mph when the lights come on the dash... any clues as to how to proceed? Faulty water temp sensor? Thank YOU!
Be sure to check the liquid level in the radiator, not just the overflow tank. How does the inverter coolant level look, and is that electric pump functioning as required? Happen to have any OBD2 codes (DTCs) worth sharing?
Which device are you using to scan for codes (DTCs) ? If you have warning lights on the dash/MFD, then you have OBD2 codes (DTCs) that your reader isn't reporting. You may want to pick up a quality OBD2 bluetooth adapter to use with Dr Prius or Hybrid Assistant : https://priusapp.com/obd.html You could also use a mini-vci cable with techstream (dealer tech level diagnostic software), and will require a windows device with a USB port. You can also emulate such with Oracle VM VirtualBox
Use techstream to scan the vehicle the next time you see warning lights on the dash, as something doesn't sound right. You might find this thread/post of interest : New here! Need help | PriusChat When was the last time the inverter pump was replaced? On a side note, have you checked the engine oil lately?
Inverter pump issue definitely throws a DTC.... have not replaced in years. Engine oil is fine. Thanks
If replaced with an OEM pump over 50k+ ago it could be suspect. If an aftermarket pump, then it might be time to replace again. Try to recreate the conditions that brought upon those warning lights, either on the road (spirited drving, w/ AC, etc) or in maintenance mode. With techstream running you should be able to determine if the engine or the inverter is overheating. Does the AC work when the warning lights are displayed, or when driving 40 mph?
I read the post you provided about the inverter pump being suspect in the problem with A/C but I don't get the connection with the engine overheating... The water inside the resorvoir of the inverter pump is churning, so I know the thing is working... are you suggesting that it could be wearing out or intermittantly working and causing the engine to overheat? I don't get it. However, I will pay more attention to other signs and signals when it happens again. I thank you SFO.
Though extremely rare, an intermittent inverter pump failure is a known quantity (as linked above), and shouldn't be ruled out. An overheating inverter loop can limit the vehicle speed, and the A/C function is one of the first things to stop working during such an event. One should expect a DTC P0A93 to be logged, and I'm pretty certain techstream logged mine under "Hist" after it cycled a few times. Was the engine overheating before the ICE water pump replacement, and did you replace the thermostat at the same time? How many miles are on the vehicle?
Please confirm that Toyota SLLC or equivalent was in the cooling system before the water pump repair, and that it was added after the repair. Just want to exclude potential sludging from the reaction of differing coolants.
You never monitored the engine temp with a scan gauge or techstream after the 'burp". I see so many people do an engine coolant flush on this site and then cross there fingers it does not have an airlock. Hope is not a tactic. It is very very hard to "burp" this car. Of course its thrown codes your dash is lit up with a fatal RTOD. If your using mini vci something ain't right there brother. It should have harnessed a bunch of codes but im pretty sure its an over heat as I will bet some $$$ you have an airlock. Or your hybrid battery failed. The aluminum head little motor will not suffer many overheats before it gets damaged. Put the heat on high. It should have great heat. While heat on high listen for gurgling under the dash. Thats an airlock. Airlock on this motor goes to the highest point which is the aluminum cylinder head. Not good.
Prius has 145k miles... Yes, coolant is SLLC. I am betting that it is an airlock too! I have not had to bleed a coolant system before and I think I am just learning how difficult it is to bleed system! So I can't work on it until tomorrow sometime and I am hoping to report back some positive news!
YUP! I added another pint or so of coolant into the engine cooling system by working the 3 way valve on TS and also working the heater motor and I got the coolant temp to stabilize between 180 and 190 degrees while driving. This was a little tedious but I have not had to do it before. Thanks for all your input!
