After the Prius was steam cleaned by a detailer, it would not start. Removed hybrid plug from hatch, removed 12v battery white cable under hood, waited 10 minutes, then car would start. But, car would not turn off. The red "door open" dash light is always on, and the red "door lock" dash light always blinks. After 2 weeks, and inspection by dealer, same problem. codes U0100 (Lost Communication with ECM/PCM "A") and U029A (Lost Communication with Hybrid Battery Pack Sensor Module). Car driven home from dealer, but vehicle will not turn off. Dash lights above always present. Then, on the way home, I rolled down all windows. But now both rear windows will not operate. I unplugged the 12v white battery cable. (I tried to unplug the ECM module under the dash, spray with WD40 and hair dryer and re-plug. Did not solve problem. I also checked both fuses for rear power windows, they are both good). I think I need to find all connectors interior to the vehicle and spray them with WD40 and dry. But, I don't know where they are. Any thoughts would help. thank you!
Did you ever figure it out?? I have same issue now after got car detailed!
@barbergc
this post is almost 15 months old and the member has not visited since then. It's unlikely you'll get an answer. You will get much better feedback if you post your own new question, and provide all the details of your situation.
I wouldn't use WD 40 on that many plastic electrical connectors... get a plas safe electrical contact cleaner. Interesting issue (I know that's not the word you feel), I'll look at schem in a bit and see if I can (theory) point you in a direction that follows the failures.
Well, I can't find anything in the service manual schematics that would be a 'single' point failure to be causing your cascade of issues.
You may get lucky by disconnecting ALL electrical (batteries), pulling apart every electrical connector you can get too inside the car. Good luck and sorry but I don't have any other info to help you other than bite the bullet and pay a well experienced Prius mech to start finding and replacing bad stuff... this will take time and $$$$. Hope I'm wrong and hope inside cleaning fixes it for you.