While driving for no specific amount of time and after coming to a complete stop, the engine starts to rev up as if I have the gas pedal pressed to the floor but I don't. Each time this has happened, I have turned the car completely off then immediately back on which stops it from happening. This has only happened maybe 3-4 times and there is no other event or maintenance task that was done to the car that may have triggered it to start happening. The car has about 220000 miles and has had the oil changed regularly along with many other maintenance items and fluid changes (coolant, inverter coolant, transmission fluid, etc.) It's been a great car.
Welcome to PriusChat!! It sounds like the vehicle is bleeding off the extra HV battery charge, this is normal if you've gone down a steep hill. How many bars is the battery SOC (state of charge) on the MFD (center screen), if it is max green (full), then this is likely what is happening. If you didn't go down a hill, and are driving around on mostly city streets, then you may have a old HV battery that is becoming unbalanced. If your HV battery is OEM at 220k miles, now would be a great time to use a grid charger setup to recondition, or top and bottom balance it. FYI : you're moderated until you've posted 5 times.
Sorry it took so long to respond, I lost track of this post. I have never let it keep going because it sounds like the gas peddle is being pressed to the floor and I panic and just shut the car off then immediately back on. It is the original battery as far as I know at 220000 Mike's so I bet it is unbalanced like you say. I have never heard of a battery maintainer for the hybrid battery on these cars.
By the way, I have not noticed what the state of charge is when this happens. What is this grid charger and how much?
