Cooling Fan issues, Inverter pump, Shuddering

Hi all,
I've had my 2010 Prius IV since Nov 2019, high mileage (267k) but generally runs ok
and gets a consistent 50 mpg, but it's not without it's quirks.

So the short version:
1. Overheating, water pump, CEL, Yellow triangle, p261b code
2. Cooling fans issue
3. Inverter pump (which I think may not be working)

Longer version
1. The car overheated on the freeway, coolant temp light came on, then about 30 seconds later it started blinking.
I was only 2 miles from my house so I thought I could make it home, but within a minute the car died and I pulled over.
The yellow triangle came on, along with the CEL and Check Hybrid System message. I noticed low coolant in reservoir. No leaks evident.
I had a code reader in the car, so I plugged it in and got a P261b code. I found out this was the water pump, so after having my car towed home, I ordered a new pump and thermostat, I figured do both at the same time.
Those are now replaced and I was quite proud of myself for doing it because I'm not the mechanic type. (Lack of patience mostly)
The w.p. impeller was turnable by hand, not seized tight, a little stiff but not freely spinnable like the new one is, where I can spin it and it goes by itself briefly.
After refilling the coolant I turned on the ign and the messages/warnings/P261b code were still there.
I started the engine for a about a minute and all seemed well. I turned it off and back on again, and the yellow triangle went away, as did the Check Hybrid System message.
But, the p261b code still shows in the reader even if I try to clear it, maybe because it's a basic reader, it won't fully clear certain codes?
So right after that I noticed a patch of coolant on the ground underneath the replaced parts, probably hadn't tightened up the thermostat enough since that rear bolt is a pig to get to.
So I went back and did that, and I noticed it was a little wet. No leaks from water pump.
I'm going to do the maintenance mode method to bleed air from the coolant, but I didn't want to let the engine run too much or drive it until I have figured out issues 2 and 3.

2. Cooling fans. It seems like they don't come on. Maybe because the air is colder due to the time of year but i haven't noticed them running lately. I've driven it all through this past long hot summer in S. Nevada and I had no problems so they must have been working.
But last time I tried maintenance mode coolant air bleed, the engine was running for about 10 to 15 minutes and the fans never kicked on.
The temperature red light came on, so i turned off the car. Later that evening I drove around for a few hours with no issues, I guess movement of air kept it cool.
Again I'm hoping this is something simple like a fuse.

3. The inverter pump. I can't hear it doing anything.
From what I have read, when you push the power button twice (without foot on brake) you should be able to hear the inverter pump whirring away. However, I hear nothing. And there's no movement of the fluid in the reservoir either (It's topped up correctly as far as I know)
The in-dash Hybrid battery level indicator shows the battery is being charged, so to my inexperienced mind this indicates the inverter is working.
I get no error code that indicates the inverter pump has failed. Could it just not be receiving power?
Is there a simple way to check a relay or fuse? I'm not sure which one to check, or how to check the pump is getting power.


Sorry for this long novel, I hope you're still awake, but ideas regarding any of this would be appreciated.

thanks

 

Thanks rj. I guess during the summer the fans must have been running while I as using the ac in that case otherwise I would have known very quickly if they weren't. It's been several months since I've used the ac but i will try it and see if they kick on.
And I have been looking at those bluetooth readers the past couple of days wondering which one to get, definitely going to get one now, and was looking at a bunch of apps like Torque Pro, Dr Prius etc. I assume they all do pretty much the same job if I have the full version.

 

Not by me, not sure if they have in the past, but it's something I'm considering doing because I do experience some shuddering with occasional P0301/2/3/4 codes. Looking at service records on the Toyota owners site, this shuddering is mentioned as a concern by the previous owner, and I can see that the throttle body has been cleaned a couple times, as have the injectors, last time that was done was Jan 2019 but no mention of the EGR

 

Yeah I'm not going to be driving it until i get it sorted. Just a question about Techstream, is that like a phone app you can download and use with a bluetooth plug in reader or is it some pricey proprietary software?

 

Only once about 6 weeks ago. The temp indicator came on briefly and went away after a few seconds. Since I was right near an autozone i went in and grabbed a gallon, it took about half a gallon and no probs until this most recent event.
Also, I ordered a bluetooth OBD reader which I should have in a couple days so I can do a bit of testing once I decide which app I want to use.

 

Actually I forgot, I had Pep boys do a coolant flush about 2 months ago because I could hear liquid sloshing from inside the dash area sometimes on accelerataion and braking. I figured that would fix it, but It didn't seem to make much difference so I don't know if they did it or just took my money without actually doing anything. Couple weeks later was when I had the issue I mentioned in the previous reply. After I topped it up I had tried to bleed the air out in maintenance mode but I don't think that made much difference either. I still had the same sloshing noise intermittently until recently. I don't know if that's cured yet since I haven't done anything else since I put the new water pump/thermostat in.

 

Hmmm, yeah I may have to although it's beyond my ability. I know someone who should be able to do it for me but I don't know if he's ever done it on a Prius.
I do not know man all this stuff is quite frustrating. Right now I wanna toss it off a cliff.

Edit: Also, can a compression test be done on this car, considering it doesn't crank over in the normal way like when you turn the key on a gas engine-only car? We did that on my wife's Camry before installing a new (used) engine once we found out it needed a head gasket replacement.
Hoping it is not the case here, don't wanna go through that again..

 

Thanks, yeah I'll try out a couple different ones. I should have my scanner in the mail tomorrow so I'll see if I can get some numbers.

 

I have a small compressor which I suspect should be good enough, it gets up to about 100psi but it should not need that much I think.
Thinking about failing HG is kinda scary, I gotta admit. It might be a few days until I can have my mechanic friend do the LD test since he works full time also. He's pretty good so it shouldn't be a problem for him and he has the gear. He was the one who replaced the engine in our Camry with me 'assisting' . If it comes down to head gasket, I know it's a job he can do as long as he's willing (and get paid!) Still cheaper than getting a new car because I would have to make payments and I have no payments on this one.
Paying a shop/dealer to fix it isn't an option, I'd just get rid of it cheap

 

Oh yeah I see the left gauge goes up to about 15 psi when he turns on the shop air. A lot less than I thought.