A system for optimizing power to a valve core movable between first and second positions includes a controller providing a control signal to the core. With the core in the first position, the control signal has a hold voltage, and the controller measures a first self inductance. The control signal is provided with an inrush voltage to move the core to the second position, and with the hold voltage to retain it there. With the core in the second position, the controller measures a second self inductance, decreases the hold voltage, and measures a third self inductance representing the core's actual position. The controller determines, by comparing either the first or second self inductance with the third self inductance, whether the core is in the first or second position. If the core is in the second position, the decreased hold voltage is applied for retaining the core there.