I am having an odd issue with the my daughters 2010 Prius II - 174,000 miles. You can start and drive the Prius in the morning when its cool, but after you drive it and let it sit in the sun (car is black) the interior heats up and quite frequently the car will not start. When you get in the power on button does not light up and nothing displays on the MDF, but the open door and a flashing lock. The key fob will open the doors, tailgate, and lights all come on. The car just will not do anything when you push the power button. If you open the back hatch and car doors and let it cool down for bit it will eventually start. So far I have replaced the 12v battery (it was last replaced in 2016) along with all the batteries in the key fobs. I also checked the brake switch - it is fine. I also have a bluetooth ODB2 scanner and I have no codes. I'm kind of stumped here. Any thoughts or ideas would be much appreciated.
Get one of these devices: Hybrid battery diagnostic and repair tool for Toyota and Lexus and install Dr. Prius app on your phone... It will show you hybrid battery temp and other data that might help diagnose.
That's a puzzle. I assume that without pressing the brake you're not getting into accessory mode either? If you haven't done so, search these forums for the repair manual download and take a look at the section called "Smart Key System (for Starting)" and see if it gives you any useful ideas. I took a brief look and it wasn't obvious to me what component would most likely cause your symptoms, but I'm curious to see how it pans out...
Yes you are correct - I cannot get into accessory mode at all. Thank you for the tip. I'll research and see what I can find. Thanks
I'm still working on this issue and sadly I've spent almost $2800 between a local Toyota dealer and a local Prius mechanic. The Prius will be fine for a few days and then will start having no-starts again. I get the following DTC codes for Smart Key system (B2786 and B278C) I also see a Power Source Control DTC code B2287. Not sure what else to do at this point. The car runs and drives great, but at this point I believe I have a wiring issue somewhere in the car. If anyone knows of a good mechanic in the Delaware area please let me know.
Those DTCs relate to the LIN Communication System - specifically the LIN bus connecting the ECUs involved here: Transmission control ("is it in Park?"), Certification (smart key), and Power management control. These ECUs are physically located behind the passenger side dash. They would be connected by harness that probably runs over to the driver side dash fuse panel. Each of the DTCs has a test procedure in the Repair Manual that includes checking specific pins on specific connectors. I'd hope that a paid mechanic would have checked those per the manual, *during* the no-start problem situation. The temperature dependent aspect of the problem makes it tricky. It would be interesting to see if a hairdryer aimed at those ECUs could replicate the problem.
Sure -- you're really gonna want to download that manual, those excerpts are just a taste. (Of course, your mechanics should have seen it already through their TIS subscriptions.)
