Hello there! I've noticed a problem with my prius today and would like some input. Normally, at almost every red light the ICE will turn off, except in certain cases when the battery is low, I have the heater on, etc. However, today, the engine did not turn off once. Even at a red light with the battery fully charged, no heater or AC on, and the temperature was about 70 degrees, not cold. Even after 20 minutes driving on the highway, the engine would still refuse to turn off at red lights. The energy display monitor at these red lights showed no energy being produced by the engine even though it was clearly on, it was just blank as it normally is during red lights. The only way I managed to get the engine to stop at a light is when I would press the EV mode button. However, as soon as I would turn it off, even if the car was still sitting still, the engine would kick back on. Any thoughts?
Nope, no dash lights on at all. I'm honestly not sure, I bought the car about 4 months ago. I believe I can find out though.
But even with the ICE off, the traction battery will feed 14V to the 12V battery. So why would a bad 12V battery keep the ICE running?
I don't know specifically how the ECU reacts to a low reading on the 12V, but folks consistently report long ICE cycles (and consequent hits to mpg) as a consequence. Maybe the computer tries to direct more current to the battery to charge it. It is a simple thing to check and rule in or out, so is a reasonable place to start - particularly if one doesn't know the history of the vehicle.
159k is not that much for a 7 year old car. About 22k per year. Just a bit above the national average. I have 235k on my 2010, but have seen a few over 300k (mostly used for professional driving). I have never used my car for professional driving. I have considered uber/lyft as a part time thing for side cash.
Well I'm interested in hearing why a Prius would do this. Our 2014 did the same thing a week or so ago to my fiancee. Yet the day I hop in it to see what's going on it has yet to do it again. She told me the engine would stay running the whole 50mile round trip drive to/from work, most of it being stop and go traffic, for multiple days. No heater, no defrost, Eco mode on since we bought the car. 50-60F. Will check the 12v battery with a load tester if the car starts acting up again.
not sure about menders b mode theory in post #6, worth testing. i have never used b in 12 years, so don't know.
