I am also getting a P1150 code on a 06 Prius (240k). Red Triangle and temp light come on after about 15min of driving (no heat). I have taken it to the dealer. They said the Coolant control valve (stuck) and waterpump (leaking) needed replacing. I replaced both of these myself along with the temp sensor, but the problem persisted. Coolant is also shooting out of te overflow hose in the overflow tank when car warms up. I just took it to a different shop yesterday because I was assuming I could not get all of the air bled out of my system. They charged me $200 and said there was quite a bit of air in the system. The first thing I did when starting my Prius was to check the heat, no heat. I drove it home and immediately noticed there was yet again coolant spitting out of the overflow tube. I didn't want to believe this was happening again. I drove it to work this morning (15min drive) and the red triangle and temp light came back on. Please help me. I have spent 3 weeks working on this and $500. The shop also said they testing the head gasket and it was fine. Thanks!
HI bills, my 08 with 245k is having almost identical problems and it's been a month with hundreds spent flushing, bleeding, replacing water pump, and buying coolant. You said that Toyota confirmed head gasket was fine but then later said a blown gasket was ur problem... can you please clarify? Thx
Apparently the head gasket leak is hard to diagnose. The same process happened in another recent thread, where it took a dealer many weeks, many attempts, and many dollars to finally find what sounded like the obvious solution. If you've had repeated high temp warnings, you probably have engine damage. In another thread you mentioned a P0420 code for a cat converter, signifying possible engine problems such as burning oil. I would take a lesson from this thread and not spend a lot more on diagnosis of a small engine with a quarter million miles on it. Sometimes these things eventually wear down.
