Hello guys, Been a long time since I have been on here. Appoligies for that but I need your help again. Details 2010 Prius Almost about to pass 252K miles temperature-upper 40s. Heater off in the car. Radio off in the car. lights off Original owner-yes bought it new with 30 miles Oil change interval: 3K miles or so Oil used: ow20 (did mobil1 for a long time, been using costco oil now for a while) Little back history I really haven't done much work on this car it over 100K miles or so. I don't remember when I did this, but back around 130-140K miles I did the following myself. changed the plugs to new NGKs Did an ATF drain and fill Did a brake fluid change Did a brake job including new pads and rotors Did a teardown of the EGR-cleaned it, the throttle body, and installed a catch can system Car was starting to burn oil and get the death rattle just before I did all of this. Since doing the above, I check the oil and catch can after every fuel up. I usually have to add 2-4oz of oil a month, and the can usually has some crap in it. In the winter time and cold, it is a lot of oily watery brown smelly liquid. In the summer there is just a small amount of darker fluid in there but not much. I would occasionally still get a brief death rattle here and there only for a minute or two on the very coldest days and when the car would sit for a few days. I keep it in the garage heated to about 58 degrees. Now onto my new issue. Yesterday when I got to work (about a 45 min drive) and parked the engine would not stop running. Usually when I get to my destination and park or while I am sitting at the light the ice will stop. After 6 minutes the engine still refused to stop running so I hit the start button and it turned off. After work when I left I got the same thing, car started up but engine would not stop running no matter what. If I pushed the EV button it would stop the engine but as soon as I went over 24 mph or accelerated quickly it would turn off EV mode and give me message about turning off ev mode. Also while driving home the check engine light came on. This morning I looked online and it said most common problems include failing 12V battery and or dirty HV battery fan. I took my meter and tried testing the battery at the front of the car by removing the fuse panel, sliding open the red cover for the positive terminal, and then touched the positive lead of my meter to it and then touched the negative lead of my meter to various parts of the cars metal, but couldn't get a reading. I then went to the rear of the vehicle, removed all the covers, etc. to get to the rear battery where I put the meter directly on my battery. It read 12.49v. I had my wife start up the car while I held the meter on the battery and after starting it was reading 14.59v. So I think the battery is good. I found my service records and I had purchased a new toyota factory OEM true start battery and replaced it myself back in 9/2022. Next I went to checking they hybrid battery fan. I have only taken this apart once before probably over 10 years ago, so after watching the nutzbotlz video to refresh myself I worked on it. I took things apart until I visibly could see the inside of the fan and stopped (didn't disconnect fan). It looks clean and not very dirty. so I tried starting the car again and noticed that when the car starts the fan doesn't spin. Not sure if it should when I first start it up. After a few minutes of running the car the fan still wasn't spinning so I turned car off. Next I looked on my phone and it was suggested to check the fan fuse and relay. I opened the battery fuse cover, and found the batt fan 10A fuse and took it out and looked at it. It didn't look blown. I check continuity with my meter and it was 0.1 which online says good. I looked at both the fan1 and fan3 blue relays. I shook them and didn't hear any rattling. I tried testing continuity on my meter with them, but either didn't get a reading or the reading was 150-160 ohms, but not sure if I was doing it correctly. I put all the fuses/relays back, and then proceeded to try to see what the check engine codes were. Using a panlong ODB2 bluetooth scanner I got off amazon years ago, I put it in and bought torque pro and got it to read the codes. It was just showing one code P0505. Looking up the code I found this The P0505 diagnostic trouble code indicates an Idle Control System Malfunction in the Toyota Prius. This code is triggered when the Engine Control Module (ECM) detects that the actual idle RPM varies significantly from the target speed or that the idle speed control learned value remains at its maximum or minimum limits Not sure if it is directly related to my problem. I also was playing around with the dr prius app. It showed no battery codes or errors, but I found when I hit "clear battery codes" there were sounds coming from the hybrid battery system and I saw the fan would start running for a few minutes. It gave me the same engine code as torque pro. This is as far as I have gotten. Not sure what to do next. I am posting this to see if you guys can give me some ideas or suggestions before I put everything back together and take it to a shop or toyota dealer. I am hoping it isn't anything too serious, as I doubt this car is worth much and was hoping to get another year or two out of it. Thanks for you help! H00si3r
