My 2011 Prius, which I have owned since new, has recently not been booting up properly. Instead, it has been going into accessory mode even when the brakes are depressed. Usually I can get it back into normal mode by turning off the power and trying again, 1-4 times so far. Of course I am afraid that the failure will become permanent. Scanning for codes with my scanner gives “no codes “. When the car eventually goes into normal mode, I have gotten a “hybrid system overheat” box for a few seconds. Since this problem usually happens after the car has been sitting for >12 hrs, that message seems like a red herring. Any ideas about what could be the problem here?
Good ideas. Brake light does come on when brake pedal is depressed. Of course, the failure is intermittent so that might not be definitive. 12V battery reads 11.1 V. Seems low to me. I will likely go get a new battery and try that.
The battery is years old. 4-6, I don't recall. But old enough that replacing it is almost certainly the place to start given the low voltage. We've owned the car since it was new. I thought the same about not depressing the brake properly when it first happened to my wife. Then it happened to me, and it took 5 attempts to get it into normal mode after shutting down the accessory mode. Not normal behavior for sure.
There is a button type switch that is behind the brake pedal assembly. As you step and hold the brake down, the button is pressed down and the car will go into ready mode. A few have said the button assembly becomes loose over time and readjusting the button switch back into place resolved the issue.
Had the same issue. Check the battery and check for phantom electrical drain if the battery is less than 5-7 years old.
