Hi folks. My 2012 Prius has displayed the temperature light lately. I've noticed it only a few times and it goes away within seconds. Also, upon starting the car this past week, the engine will occasionally run very roughly. This clears up before I can get to the end of my block and only happens at the first start of the day. I pulled the following codes: P0117 engine coolant temperature circuit low input. P0301 cylinder 1 misfire detected P148f engine coolant pump over Revolution I assume that the shaking engine is related to the misfire. But I'm not sure why it only happens in the morning. Are these issues somehow related? My copy of Techstream is a bit wonky in that it won't let me see live data without an error. So, I'll need to get another way to see actual running temps in real time. But I did notice a recording of 275 degress! My hope would be a bad temp sensor. But, if the possible high temps are related to the misfire, I worry that the water pump is failing. And there is that P148F code. I can't find much good info for that code but it does seem to lead to a water pump replacement. But I wonder what the heck "over revolution" exactly means. A YouTube video offhandedly mentioned that there were 2 speeds to the pump. Could it be that the lower speed is for safe running temps and that the higher speed is for abnormally high temps and that this would be referred to as "over revolution"? Any help or ideas would be greatly appreciated.
The electric engine water pump failed and caused the engine temp to spike. This may or may not have caused the head gasket failure. Monitor your coolant level and see if it has been dropping. Most of the head gasket failures have been on cyl 1 or 2 and will cause coolant to leak down into the cylinder(s) overnight. This causes the engine to run rough (and misfire) until the coolant intrusion gets burned off. How many miles do you have? Around 150k?
It might not be Techstream. That was happening to me when I was using a Mini VCI dongle. Bought an Openport and plugged it into the same laptop, same Techstream, et voilà, live data, no error.
Mileage at 177k. God, I hope the head gasket didn't fail. But what you say makes sense. I did notice the coolant a bit low. But, to be honest, it may have been low when I picked it up some months ago. It's strange that I haven't seen the temp light in several days and it's been a few since the last rough start. I guess I'll replace the pump and cross my fingers.
Order an Aisin WPT190 from Rockauto for $238.79. It is the exact same pump but with the Toyota logo ground off.
If I were you, park your car for at least 12 hours. Then, remove the spark plug for cyl #1 and #2. Use an inspection camera (you can order a $40 one from amazon) and check for signs of coolant (or any liquid) inside of the cylinder. I strongly suspect that you have a failed head gasket.
It was maybe a week ago that that I noticed the low coolant. The reservoir may have been about half full so I topped it off. Well, I just checked and it was nearly empty. I'd say it's a new pump and head gasket for me. Someone tell me that I'm wrong. Is the head gasket a diy project? I'm no mechanic. But I typically figure out and fix whatever pops up on my cars, including rebuilding the traction battery in my old 2006 a few times, just swapping modules. But this car is my moneymaker (Uber), so I can't have much downtime.
2011 Prius Head Gasket Failure at 185k - Summary - Bob Is The Oil Guy I also have a thread on here, see the link in my signature.
Mcgeorge toyota is actually cheaper than rockauto @ $198.47 for the water pump and $178.69 for the complete engine gasket kit. thank you for your posts. just parked my car in the garage to start on the HG repair on my Lexus!
