I'm not a technically knowlegable on a whole, but i gather if the phase sensor is connected to the ecu.

This would result in very minimal but drivable status, the reason for this is that the ecu recognises that there is a problem with the sensor and thus substitues the the data that is is meant to be sent with stable dummy data in order for the vehicle to function but at basic potential.

Like backup power if something goes wrong, i would presume for the majority of the sensors this type of function would occur if in contact with ecu.

Please if i'm wrong correct me.