Today i was messing with the newly installed scanguage II and i set it on mpg and the dash readout and the scanguage readout was way different. the dash said at 50mph flat and level was about 48 the scangauge said 34 WOW what a difference. Anyone else have this happen?
Have you completed the full setup and calibration of your ScanGuage as detailed in the manual? If not, go with your Prius' display.
I would have to ask the same question as prim2. If you haven't properly calibrated the SG2, it may still be set to the default of a 3.0L engine which would give a reading that is way lower than the FCD.
I would suggest that you use pen and paper, and track all of your gas fillups and your mileage, and do the math.
I'd double-check the engine size again... Theres a chance you forgot to save or the SG "forgot" your settings... You wouldn't be displaying the trip mpg data would you?
im pretty sure i did everything right but tomorrow ill double check it again. Supposed to be a high of +7 here tomorrow with wind chill in the - 10 range brrrr. im so glad i work outside !
I dont know what buttons i hit to screw it up but i reset all the defaults then did setup again and now its fine. Duh !
Even using the recommended calibration procedure, the SG can still be way off. (After 6 months, I still haven't gotten mine right). There is a spreadsheet on CleanMPG.com that will get you closer, if you can figure out how to use it.
