Unexplained Prius Starting

are you over 50?

 

It could possibly your AC is running since you have a solar panel with sunroof. That's my only guess since when you opened the door, the vehicle stopped running.

 

Did you happen to accidentally trigger the remote AC function with the key fob?

 

I would also assume that the A/C button was pressed on the remote which would have triggered your vehicle to start air circulation. This would sometimes require the engine to start to keep the battery charged. The ICE shutting off upon opening the door is normal behavior if the A/C or Remote start features were activated.

 

The solar panel package remote AC won't start the engine.

Is it possible that you heard the AC compressor and cooling fans running and assumed that the engine was running?

 

i'm only going by personal experience.

 

In short?
I hang around Prius Chat way too much, but I think I can safely say, no the problem you describe is not a commonly presented problem.

Are you both 100% sure the vehicle was turned off? And are you simultaneously 100% sure that when you approached it what you heard was the engine actually running and not just fans or the circulation system or AC?

My only advice would be that a running vehicle, even a Prius, in an enclosed space can be dangerous. If you have a 1 in a Million defect where your Prius for some reason doesn't shut down properly or can restart itself? You don't want an environment that puts your life at risk.

Otherwise? I'd file it for now under fluke or possibly misunderstood circumstance.

 

Sounds like you had the keys in your pocked and pressed the A/C button which can start the ICE if the traction battery is low enough. The fact that the engine shut off as soon as you opened the door means that the car was started externally (not by leaving it on from the inside).

 

The system will not start the engine.

From the owner's manual:

Operating conditions The system will only operate if all of the following conditions are met: l The shift position is in "P". l The "POWER" switch is OFF. l All doors are closed. l The hood is closed. l The brake pedal is not being depressed. l The air conditioning is not set to MAX HOT.
Remote Air Conditioning System automatic shut-off
The system will automatically shut off under the following conditions: l About 3 minutes have passed since operation began l Any one of the operating conditions is not met The system may also shut off if the charge level of the hybrid battery (trac-tion battery) drops to low. (→P. 191) n

Conditions affecting operation The system may not start in the following situations: l The charge level of the hybrid battery (traction battery) is low (→P. 191) l The air conditioning temperature is set at a high level.

 

^^ thanks for pointing that out. My mistake.

Does OP have a factory remote start?

 

We'll just have to wait for op to answer our questions before we can guess what it is next.