So I am sure this is very common and yes I did search. I bought a 2005 Prius with 190,000 that had sat for a year. Bad hybrid battery Bad accessory battery New Hybrid battery and new accessory battery and she drove great-- AWESOME! So, I drive it for I don't know maybe around 100 miles or less and decided to do full tune up-- I drained engine coolant and inverter coolant and bled them. Immediately I start getting P1121 code after driving. Bleed again-- P1121. Order new used DENSO OEM valve. And same exact thing. It keeps coming on. I took my old valve apart and couldn't find anything wrong other than what looked like some corrosion on the potentiamitor/sp? inside. I do not have techstream. I am getting zero bubbles from coolant system when I bleed and have jumped the storage tank pump connections, am not overheating while driving etc. Are there any fuses to check that are related to this system? Anyway to force the valve 12v and put it in a certain position?
Pretty sure that is something that can be done from within techstream. Have you already walked through the work up for DTC P1121 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/2054m/cip1121a.pdf
Probably time to go to The Last Resort (a/k/a the repair manual, more info) and look up how to troubleshoot a P1121. As the detection condition may involve signals getting back to the ECM from the valve position sensor, it may take some quality time with a multimeter and following the prescribed troubleshooting steps to find the source of the problem.
Yeah, I am also starting to think about head gasket failure. I see no signs (no mixed oil, not a lot of bubbles coming from coolant) but sometimes when running the car for a while in the inspection mode there seems to be a decent amount of white smoke coming out exhaust even after it is warm. I don't know yet I am going to keep driving it, just very frustrating that I have replaced the valve now and nothing changed at all. I am wondering if the valve has to be set to a certain position before being plugged in so the computer knows where it is?
Honestly, there were misfiring and rough-running engines for years before EGR was even used. It doesn't have to mean they have blown head gaskets either. There's the whole rest of a fuel / compression / ignition cycle there to be investigated. What are the codes?
Yeah if you read my initial post that was what I am saying. As someone that works on a lot of cars I hate throwing parts. I threw a coolant valve at it and likely two being bad with the one that was in the car taken apart (by me) and seeing no noticeable problem at all-- that likely I am dealing with some other problem. Was just seeing if someone had any other ideas becasue I don't have techstream and bleeding it or testing it isn't as easy. Or if I can just give it 12v and ground while it is in the car and check its movement froward and back
There are also wires involved. If the valve is fine and the position signal isn't getting correctly back to the ECM, you'll get the code. So troubleshooting isn't just limited to the valve. That's where the repair manual will help you out. Whether or not you have Techstream, if you have a multimeter, you can see the circuit overview in the manual and the troubleshooting procedures, and check stuff.
Yes, basically now I would like to know where to get the full manual to see wiring diagrams and locations. The link provided has a lot of external links I can't access since I don't have those parts of the manual. Any help appreciated.
techinfo.toyota.com is where you can get everything. I'm gonna guess the "used" part is probably a problem
2005 Toyota Prius HYBRID Accessory Power Relay. Electrical, SWITCH, ENGINE - 8264147010 - Genuine Toyota Part As already posted, techinfo.toyota.com is the ultimate source for the manuals and wiring diagrams, but @Elektroingenieur kindly compiled a wiki page describing a lot of other options for getting the information.
I replaced it with brand new unit. I have the tricks to do the job in like 30 minutes (minus bleeding coolant) unless you have airvac bleeder. Trick: Lift inverter place on blocks. Remove wheel fender curtain. Drain coolant from storage tank. Remove hose from the valve at the tank. Remove two two hoses (mark lower one with paint so you know). Remove 12mm and 10mm nut and bolt respectively. Wiggle valve out the top (a struggle be careful not to break anything-- move inverter around if needed (more hands and eyes helps to see what it is catching on). Reverse procedure. Bleed using 6mm allen bleeder bolt, heater on, and manually pumping storage water pump. Drive it around with coolant cap off heater on high with scan tool making sure it gets above 185F. Pull over top up and put coolant cap on (some will have spilled). Monitor coolant over next couple of days.
