ScanGauge tuning

[vectorg]

I have learned from using my ScanGauge for several months that it registers my trip-mileage at between 25% and 33% low.

What is the menu or key-sequence for me to make this calibration to my ScanGauge? I read the manual about a method to calibrate when doing fill-ups, but didn't see a general adjustment like I need.

Is there a way to make a general calibration like this?

Thanks.