Does the ScanGauge II support metric units?

Yes, the units of measure can be independently selected between Miles/Km, Gallons/Liters, Celcius/Fahrenheit, and PSI/KPA.

If you choose Km and Liters, fuel economy is reported as liters/100Km (LHK).

If you use Imperial Gallons when you do the calibration, fuel will then be adjusted to use Imperial Gallons.

When I press SCAN it says -Not Ready- in the lower line. How can I tell which OBD test has not been completed?

There is a way to do this using the CMNDS feature in the ScanGauge II. See Finding Incomplete OBDII Tests Using the ScanGauge II.

What is FRZD in the ScanGauge?

When a trouble code is set, the data at that time (RPM, Coolant Temperature, Speed, Throttle Position, etc.) are captured like in a freeze frame. FRZD can be used to recall this data to help diagnose the problem.

The MPG gauge reading changes very quickly with slight changes in throttle or load. Can I smooth this out to better determine the affect of speed on fuel economy?

Yes, use the TRIP MPG function in the CURRENT mode. After reaching the desired speed, reset the TRIP. The average MPG since it was reset will be reported.

Do I have to reset the trip computers for each trip?

No. The CURRENT trip can be reset manually if you desire. It is automatically reset after the ignition has been off for more than a few minutes. The DAY trip will accumulate the entire days trip information and reset itself after the ignition has been off for more than 8 to 9 hours. The DAY information is moved to PREVIOUS before it is automatically reset.

Can I tell how high the coolant temperature has been getting on my wifes car?

Yes. The maximum coolant temperature is stored by the trip computer and can be read back by you later.

My speedometer only goes to 90MPH. Can the ScanGauge II show speeds above this?

Yes, the ScanGauge II can show speeds up to 158MPH.