Both Kwikee and LCI(SCS) steps use current limit as the stop. Once the step motor reaches a preset amp draw, the controller cuts the voltage to the motor. The amount of amp is not a concern to me as Kwikee and LCI have never told me that. I have NEVER had a faulty controller that the amp limit was bad. This is why you can park next to a curb or any obstruction and the step will cut off if it cannot reach full extension. This is also why, when you have neglected the lubing of the step linkages, the step only extends or retracts partially. Doug