A start system includes a vehicle bus system disposed in a motor vehicle. A powertrain control module is connected to the vehicle bus system. The powertrain control module includes an engaged state electrically enabling the powertrain control module to provide tractive power to a vehicle drive wheel, and a disengaged state electrically inhibiting the powertrain control module from providing tractive power to the vehicle drive wheel or another vehicle drive wheel. An authentication system is in communication with the vehicle bus system and with an electronic pattern-entry user interface. The authentication system is responsive to an entered pattern entered on the interface while the powertrain control module is in a current instance of the disengaged state. The powertrain control module enters the engaged state only in response to an authenticated engagement command communicated from the authentication system to the powertrain control module in response to authenticating the entered pattern.