Providing online non-downloadable software for use in diagnosing, maintaining and repairing trucks and truck engines, for providing service advice and information in the field of repairing trucks and truck engines, for ordering spare parts for trucks and truck engines, for tracking service information related to trucks and truck engines, for communicating with and reporting information from on-board vehicle control and diagnostic units, for reprogramming electronic control units on vehicles, and for running tests, running calibrations, and changing parameters related thereto; Providing online non-downloadable software for use in diagnosing trucks and truck engines; Providing online databases for reprogramming electronic control units on vehicles, and for running tests, running calibrations, and changing parameters related thereto