5. The system of claim 1 , wherein diagnostic information relating to said onboard vehicle control network is retrieved from said database in response to a request received from said portable wireless diagnostic unit after being entered via said manual input interface.
5. The system of claim 1 , wherein diagnostic information relating to said onboard vehicle control network is retrieved from said database in response to a request received from said portable wireless diagnostic unit after being entered via said manual input interface. 6. The system of claim 5 , wherein said information relating to said onboard vehicle control network comprises graphical information relating to said onboard vehicle control network, said graphical information being displayed on a screen display at said portable handheld wireless diagnostic unit.