I haven't had my Scanguage very long so it may be user error. When I fill up my gas tank, there is about a 1% difference between miles on my trip odometer and miles on my scanguage. It always seems like the scanguage is 1% less than the trip odometer. Just today, the trip odometer read 392.2 miles and the scanguage read 388. I reset both the trip odometer and scanguage when I fill up.

Is this normal? Which one do I believe?

 

Have you followed the instructions on calibrating the SPEED in the manual for the ScanGuage?

 

Yikes, RTFM. Guess I'll have to check that out. Thank you.

 

That being said 1% isn't that far off. I calibrated mine with a handheld GPS... got on the freeway and set the cruise to 60MPH indicated by the GPS and made my adjustment on the Scanguage. Mines pretty close, but it might be still 1% off. 1% is pretty darn good..