Just thought I would add this for you. Info from Here
Modern cars have a built-in diagnostic system called OBDII or EOBD which your garage will plug into to help determine any faults. You can now plug into this system yourself. Find out what is really wrong with your car before taking it to the garage. Check for faults on second hand cars before buying.
•Diagnostic scanner features.
•Analyses faults identified in the car management system.
•Displays fault code explanations on screen.
•Additional freeze-frame information and test results storage function for off-car analysis.
•Styles and designs may vary.
•Compatible with all petrol engine cars manufactured since 2001 and all diesel engine cars manufactured since 2004.
•Read and reset fault codes.
•Reset check engine light.
•Size H20, W8.5, D3.5cm.