Scantool

Check this link right here http://www.totalcardiagnostics.com/toad for more information on ScanTool. Most flash codes use a combination of long and short flashes to indicate double digit codes, and if the vehicle has more than one code, it may be tricky to tell when one code ends and the next one begins. So the preferred method of reading codes on older vehicles is to use a code reader or ScanTool.