1. A vehicular diagnostic tool for receiving vehicular diagnostic codes from a vehicle on board computer, and translating the diagnostic codes into diagnostic descriptive data comprising: an input port for receiving vehicular diagnostic codes output from a vehicle under test; a code parser for parsing the received diagnostic codes into diagnostic code segments; a code translator for correlating diagnostic code segments to corresponding diagnostic descriptor segments; and a combiner for combining the code descriptor segments to derive composite diagnostic code descriptors, the composite code descriptors being collectively representative of the received diagnostic code.