How to stop or freeze the EV3 large motor in position
According to the official documentation you could use
hold()

which

Stops the motor and actively holds it at its current angle.


Note: My assumption here is that you are referring to this

as &quot;large motor&quot;. If you are using a PF Large Motor:

then this advice is useless, as those can't be controlled with such precision due to the lack of an internal rotation sensor.