Water pump and Coolant pump

Tiny
FLORANG2123
  • MEMBER
  • 2011 TOYOTA PRIUS
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 184,000 MILES
A while ago I got the codes p261b and p148f. I replaced the water pump in my car, and everything got fixed. However, 1 month later it started giving me those same codes again. I don't know what else it could be. It was recently replaced so why is it giving me the same codes? Also, the coolant seems to be running out faster than it should. Hopefully, someone can help me with this. Thank you.
Friday, January 14th, 2022 AT 2:35 PM

3 Replies

Tiny
AL514
  • MECHANIC
  • 4,793 POSTS
Hello, these codes can be set if you are losing coolant due to a leak or possibly a head gasket issue. The first code (P261b) can sometimes be taken care of by properly bleeding the coolant system, so if you're low on coolant it can set both of these codes. So, the real issue to begin with is finding out where the coolant leak is. That is probably the overall cause of these codes. The P261b is the ECM detecting the coolant pump below 900 RPMs so the code trouble area is labelled as 1. Open or Short circuit in engine water pump assembly circuit. 2. Engine water pump assembly 3. ECM issue,
The p148f Problem Area is. 1. lack of engine coolant, 2. Engine coolant leak, 3. Engine water pump assembly.
And the code detection for that one (p148f) engine water pump assembly speed has been more than the target amount.
So, the first thing is to determine the coolant leak. Since you said you're actually missing coolant, that is your main concern. Doing a pressure test on the coolant system will help determine where the leak is. If the coolant is low, I can see how the pump can actually spin faster than it should since there's a lack of coolant/pressure to push.
If it's only been a month since you had the pump replaced, you should be able to bring it back to the place that replaced it and explain that it's losing coolant. They should have checked for a leak to begin with if you were getting these codes. Not just replaced the pump without checking the system completely. Especially on a system like this where the engine computer monitors the pump speed and circuit conditions. I will post the code definitions in just a minute.

https://www.2carpros.com/articles/radiator-pressure-test

https://www.2carpros.com/articles/coolant-leak-symptoms
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Friday, January 14th, 2022 AT 4:48 PM
Tiny
FLORANG2123
  • MEMBER
  • 9 POSTS
Thank you so much for your help! I understand now what you described as the possible causes.
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Friday, January 14th, 2022 AT 8:34 PM
Tiny
AL514
  • MECHANIC
  • 4,793 POSTS
No problem, I hope they take care of it for free, they really should.
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Saturday, January 15th, 2022 AT 11:18 AM

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