ScanGaugeII will not allow you to reprogram the TCH's internal settings.

It can, however, report the normal Diagnostic Trouble Codes (DTCs) from the OBDII port with its associated Freeze Frame Data, and also erase the DTCs. It has the ability to memorize 10 customized query code strings to be sent to the on-board computer — but you have to know the strings to send. It stores trip information for the current trip (since the last start), for today, for yesterday, and also cumulative data for the current tank of gas. This trip information includes not just the distance travelled, fuel used, average fuel consumption, etc., but also maximum coolant temperature reached, maximum speed, etc. This is much more versatile than the TCH's readouts.

For me, the reason for purchase was to be able to have a real-time display of various sensor readings, so that I can see what's going on with the ICE. One can display, amongst other items, ICE rpm, ICE % load, water temperature, fuel usage per hour rather than per distance, etc. This has helped me understand what the ICE is doing at different times. The fuel economy readout spans a much greater range than the dashboard display.

Stan