Prius 2nd gen (2005-2009) ran totally fine, but Smog Check wouldn't pass unless we get these codes P1116 and P1121 cleared. P1116 - Coolant temperature sensor circuit stack for coolant heat storage system P1121 - Accelerator position sensor range / performance problem The Fix The fix seems to be to replace the Coolant Control Valve. Mechanics quoted me anywhere from $500-800 Depending on how much you make or your condition, this may be worth it. For me, $500-800 is A LOT of money. Doing it at home is ~$200 + up to 3 hours of your time ( If I have to do it over again after my hand recovers, I can probably do it in a hour ) Here are the tools needed to do the Coolant Control Valve replacement on your 2nd gen Prius replacement yourself Toyota Coolant Control Valve - Part #16670-21010 - $120 - Make sure you buy the genuine Toyota. There are plenty of parts claiming to be genuine on eBay, but there are plenty of counterfeits floating around for $40, Several people on youtube / forums have stated their CCV has quickly given errors from buying cheap alternatives on Amazon or counterfeits on eBay. We bought ours from a local Toyota dealer for $115 Socket Wrench Size 10mm and 12mm - This is to remove the bumper / headlamp / Coolant Control Valve. If you have any mechanic's toolset, you probably already have these. If not, just buy or borrow a basic set from Amazon or your friends Hose Clamp Tool or a Bent Nose Plier - $15 - This is to remove the coolant hose from the CCV Cork Screw - $5 - This is to stop the coolant from spilling out too much Coolant Refill and Funnel - $20 - This is to refill the coolant after all is done I used the method to take off the headlight since I have bigger hands. I still got pretty beat up This video saved my life, BUT 1. I used corkscrews to plug the hose 2. I did not unplug the batteries I also watched this video to refill my coolant properly It really ended up taking about 5 hours honestly because I took breaks in between and was very careful with everything.
So are you driving and done because the code is talking about the coolant heat storage tank coolant stack. So I would think there's some kind of issue with the temperature sensor on the coolant heat storage tank which is in the lower left fender behind the splash shield easy to get out of make a 14 mm rental unscrew it and I would imagine you can buy that temp sensor from all kinds of manufacture I have quite a few of them on the tool table.
Good work on your repair. Slow and steady wins the race. Stack is a translation error/typo. The correct work is stuck. It has the same typo in the repair manual, but further on in the text, it says stuck not stack. FYI, the cookie cutter text might be what P1121 is in some other car but that is not the correct text for your Prius. The correct text is: P1121 - Coolant Flow Control Valve Position Sensor Circuit Stuck.
