Powered retractable vehicle step assist systems and methods are provided. The steps systems are configured for installation (e.g., after market installation) and use with a vehicle. The system can include a stepping member movable between a retracted position and a deployed position with respect to the vehicle. The system can further include a vehicle interface configured to electronically communicate with an existing communication bus of the vehicle, such as through a connection with an existing electronics port of the vehicle. A controller of the step system can be configured to process information received from the vehicle interface and, based at least partly on the processing of the information, cause movement of the stepping member between the retracted position and the deployed position.