The embodiments include a handheld mobile device (HMD) operable to cause a subsystem of a vehicle to perform a vehicular operation associated with an existing capability of the subsystem. The HMD includes a processor, a port operable to communicatively couple the HMD to an existing on-board computer of a vehicle via an existing data link connector of the vehicle, and a wireless interface operable to communicatively couple the HMD to at least one of the vehicle or a remote service. The HMD further includes a memory storing a software application that, when executed by the processor, causes the HMD to communicate a command to the on-board computer via the data link connector to perform the vehicular operation associated with the existing capability of the subsystem.