Is there a way to put a 2010 Prius into neutral with the P-Lock engaged

Question

Is there a way to put a 2010 Toyota Prius into neutral with the p lock engaged?

Answer 1

First you should consider how a Prius works.

There is no clutch. No torque converter.

Instead, there is a planetary gearset. The wheels and motor-generator 2 (MG2) are directly connected to one shaft. Another shaft goes to the internal combustion engine. A third shaft goes to motor-generator 1 (MG1).

Activating neutral in Prius means that all electric current to motor-generators is stopped. They are left to rotate at whatever speed they want. If the engine was running when activating neutral, it can stay running. But if the engine wasn't running in the first place, the Prius is unable to start the engine in neutral since you need the motor-generators to do that, and the definition of neutral in Prius is "no current to electric motors".

The parking position, on the other hand, stops the rotation of wheels and MG2 with a parking mechanism, and allows whatever current the car computer wants to use at MG1. So it's possible that the internal combustion engine is rotating MG1 which is used to charge the high-voltage NiMH battery. It's also possible the high-voltage battery supplies energy to MG1, which is used to start the internal combustion engine running.

As far as I know (I don't have a 2010 Prius but 2016 RAV4 hybrid), there is no position that would both have neutral and parking mechanism active. However, you can come close by using the parking brake and switching to neutral. If you do so, the car won't move, and the engine can't be started and the HV battery can't be charged.

It's beyond my understanding why you would want to do that. If you leave the car unattended, it may turn off, since there's no way for the engine to be started once the NiMH battery runs out of energy. And if the engine was running in the first place, there's no way to charge the battery.

Use the car in a way it's intended to be used. If you park, leave it in "park", which means the car is able to start the engine if the NiMH battery runs out of energy, and able to charge the NiMH battery. All the extra the emulated "neutral" gear would do is to prevent the engine from being started and prevent the battery from being charged.

And if you don't want the engine to be started automatically, just turn off the power. Then a relay switches off all current of the HV battery, meaning it will hold its charge for months.