A method of diagnosing a status of a vehicle. The vehicle has an on-board computer for generating a diagnostic trouble code signal related to a passed or problem status of the vehicle. A portable code reader is connected to the on-board computer. Diagnostic trouble code signals are communicated from the on-board computer to the code reader. The code reader communicates to a personal computer respective ones of the diagnostic trouble code signals related to a problem status of the vehicle. The personal computer communicates the respective ones of the diagnostic trouble code signals from the personal computer to a remote computer. The remote computer is configured to correlate the diagnostic trouble code signals to problem description data for diagnosing the vehicle. Problem description data correlated to the respective ones of the diagnostic trouble code signals are communicated from the remote computer to the personal computer.