My daughter was driving her 2012 and said she got the message ‘cooling performance of the hybrid battery is low consult a dealer. I was hoping it was a dirty fan but then she called and said after about 4 or 5 miles the car died and wouldn’t start. I had it towed home. It won’t start and has the message “check hybrid system - park car in a safe place’ wont go into gear, no power steering etc. I checked the aux 12 volt last night, 11.9 v, charged it overnight and got up to 12.4 volts. Still no start. ‘checked all fuses under the hood. All are fine. Hooked up scanner - no codes. I’m baffled.
Welcome to PriusChat!! Not sure which scanner you're using. Many here prefer a mini-vci cable, and a copy of Techstream (same software used by the dealership). You could also try a bluetooth/wifi OBD2 adapter with an App like Dr. Prius (aka Dr Hybrid), or another App like Hybrid Assistant. Here is a sub forum if you are interested in that knowledge : Prius OBDII Third-Party Apps | PriusChat A link for identifying the right adapter : Hybrid battery diagnostic and repair tool for Toyota and Lexus Since this was posted in a gen2 sub, I've flagged a moderator to have it moved into the appropriate gen3 sub.
Airflow can be restricted not only by a dirty fan, but also by any objects blocking the cooling air inlet duct, which commonly happens on the gen 3s by objects on the rear seat passenger side area. If you need to get the car going again, you could reset all faults by disconnecting the 12v battery for a minute or two. That should reset the ecu's and allow the car to start working again.