Water pump failure Symptoms

The Gen3 water pump is a magnetically driven pump. Once you have the new one installed and ensure it is working properly, might be worth taking the old pump apart and see if the magnets are all attached or something isn't right.

 

My observation with both my original, 140k miles WP and a brand new Aisin replacement has been ~2600-3000 rpm from cold start, open loop up to mid-190's F closed loop. I may be wrong but think the 6k rpm readings are an indicator that the P261b is for real. In seeing the OP's bad pump impeller not spinning smoothly, believing 6k rpm was actually happening is doubtful to me. Maybe a cooked resistor or something sending funky voltage to the ECU and Techstream?...

Also, I can confirm the Aisin part number pump does indeed come with the "Toyota" and "Aisin" casts ground off. There was a poster recently claiming widespread counterfeit pumps as he was replacing his WP like changing underwear. It turns out his wiring harness connector was packed with green crusty's and he likely had swapped out several, perfectly good OEM pumps when all that was needed was to clean the contacts.

Here's a pic of my eBay, Aisin branded pump:

 

Great descriptions MeGuinness and others!

Until now I haven't known the symptoms for a failing water pump.

Pixel XL ?

 

Good work meguinness, glad it all worked out

 

I just replaced my water pump on the gas engine. No code at first. I check my oil regularly. I first noticed coolant being shot out of the reservoir. I'm thinking thats weird never done that before. I top it off never drops to the add mark. Fast forward about a week later. Saturday morning coolant light comes on the car is barely on 5 mins on the freeway. Stays on for a few seconds then shuts off. I drive a 35 mile commute. Next day on Sunday while driving to work in the morning boom MIL " check engine " on, lose power. I pull over check coolant oil everything looks normal. I baby it to work about 15 mins, very risky but I'm keeping an eye out. Get to work pull the code P261B. Prior to the light coming on I'm thinking the thermostat or water pump. No smoke no smell just small amount of coolant around reservoir. Whats funny I had it at the shop where I work for a few days waiting for the part to come in. I'd let it warm up move it out and move it in at the end of day. The check engine light disappeared on its own. No " check hybrid" warning either. I still cleared all the memory prior to installing the new pump.

Been driving roughly 500 miles since the replacement. No check engine or no pending codes no coolant light no more coolant being shot out. Also enjoy driving without the silencing tubing for the intake.

Thanks for the videos Raytheeagle on the EGR cleaning. I may need to hit you up on that spare cooler so it can buy me time to clean mine.

2010 Prius 155k

 

We just had a meet up today in Lafayette :

Possible Monthly install meets. Bay Area-Fremont

Anytime you want to meet up or need assistance, let me know or monitor the thread and we'll see what we can do.

 

To OP- can I ask where you ended up getting your replacement water pump in the end?