I have a scanguage also, but I haven't used it on the Prius yet-just the non hybrids. I'm pretty sure the scanguage just looks at fuel flow and speed to get an instant mpg or trip mpg. MILES/HR divided by gallons/hr is M/H x H/G=M/G or miles per gallon.All cars"know" their instant fuel flow,and they all know their speed.

I think only the most recent scanguages are set up for Hybrids.They had problems with the engine shut off,and thought the trip was over.I think you can return the scan guage to be updated for hybrids.Luck,Charlie


PS I just -Monday 5-8-06 3 pm Central time-tried the scan guage out on the Prius during a short trip. The speed and MPG on the scanguage are just about what the Prius screen says they are. The most interesting thing was the RPMS. At 32mpg -on ICE only- the gauge said it was doing ~1250-1300 RPMS. This is interesting because our 2001 Prizm(rebadged Corolla) would show about 1450 rpms in top gear(auto) at 32mph. The vehicles are about the same size, but the Prizm is about 150 lbs lighter, and a couple of inches less in height. It also has a BIGGER(1.8L),MORE POWERFUL motor-125 hp . I'm surprised the Prius can run such low RPMS. I will check the RPMS at 60 miles per hour,70 miles per hour,75 miles per hour, some time soon. My guess is 2500 rpms at 60 miles per hour-this is about what our auto trans 1995 Accord would turn-it was 2.2 L I think.Low RPMS is also a good sign; less fuel wasted as friction.The low CD certainly helps drop the load so it can run low rpms.Thanks,Charlie