P261C and P261C* is it inverter or engine water pump?

so the problem was FUSE#5 in the engine compartment, 30A ( found a spare).

I did not erase error codes initially, but then I did. I will erase them now.
seems to be working. I was affraid to test old pump, since if it is short circuit inside it will probably blow another fuse.

 

Hrm, is that fuse for the water pump or was it for something else?

 

I think it is listed as "cooling system".

 

Interesting... well if you had a mini VCI, it would've helped in diagnosing the old water pump. I'm glad it worked now

 

I just checked the wiring diagram, there is a 30A fuse for the water pump assembly... I'm wondering what caused the fuse to be shorted and if the new water pump that you installed didn't short the water pump, did the old water pump shorted the fuse or something else did?

Hard to tell... but if the water pump is working properly right now, I wouldn't want to mess with it.

 

but for the posterity:
CHECK THE FUSE : )

there is a reason why the pump blew the fuse I think. dont want to mess with it though. All the symptoms before, overheating etc, the pump was probably on its last legs.
PS:
I got the thermostat before it went down, and wow, that is a hell of a job if You have to replace thermostat! absolutely no access to the "3rd" bolt that holds it in place! have You tried replacing that ?

 

PS2:

the only problem with removing those bolts is to find correct size of an extension for the socket! it has to be just right for the little room that is left there - I had to use flexible one, which was a pain.

out and new in took me ~2h, but I was not rushing really.
also, if You are draining coolant, You can get away without removing the plastic cover, just connect flexible pipe so that You can drain it cleanly. Opening valve can be reached via one of the "holes" in the plastic panel ( I was affraid to remove those rusty bolts that hold it, wasnt sure if they will easily go back : D )

 

Nice work, good to know in case I need to replace mine in the future.

 

I have a 2010 Prius. It started having issue at about 203k, check engine light on. Pulled code: P261b. Replaced Eng W/P. Condition code cleared. Ran for a month, then check engine light and glowing triangle. Now codes are P261b and P261c. Watching live data off ODBII - water temp went up to 100c. Check fuse number 5 - fine, checked socket for W/P - no issues visible. Checked power to the plugin socket to W/P 14.2 vdc. What is the best course of action. Will buying a mini-VCI assist in trouble shooting? Is there a relay downstream of the W/P 30 amp fuse that might be going bad? Whats the odds that pump is bad again?

 

I had the same exact problem. 2015 Prius two @200k miles. Car stopped on me while I was driving and had to have it towed home. Kept getting p261c and I had already replaced the water pump a couple years ago and probably drove about 50-60k miles on it but it was aftermarket brand so I figured it went bad and replaced again but code still kept coming right back up after erasing. I read this forum and checked 30amp fuse on my car it was location # 2 in my engine compartment it was labeled ENG W/P Cooling system, and it was a blown fuse. I wonder if the old water pump caused the fuse to go bad? when I checked the water pump it was spinning relatively smooth. not as smooth as the new one. The new water pump had a little bounce to the spin. Old one didn't. When I took off the pin and pulled out the magnet it looked new. Going to replace now and see if it takes care of the problem. I'm glad I saw the blown fuse. I read other forums to replace the inverter pump which is a tricky job to do at home.