A testing system for interfacing with a vehicle diagnostic system and performing a diagnostic test on a vehicle. The testing system includes a housing configured to at least partially retain a processor in circuit communication with test circuitry configured to selectively communicate with vehicle's onboard diagnostic system via a test cable. The test cable retrieves diagnostic data from the onboard diagnostic system, and the processor performs a diagnostic test which is sent to an output device for displaying the test results. Results are transmitted to a computing device comprising an application system having an interpreter for displaying diagnostic data on a display of the computing device.