Here is a link with a better list of Xgauges for your truck:
Some Scangauge II Codes for "Xgauge"
Here is an example of the codes you will need to enter. It is actually simple to enter these gauges, just be accurate in your entering. As you see below you will always enter TXD first, then RXF and so on. The Scangauge II will walk you through these steps in this order.
Now, you will find Xgauges through out the link above, some will have the "TXD"-"RXF" listed, some wont. Just know, those that do not have these letters are still listed in this order. Have fun!
(also, the Scangauge II as you scroll through, the Xgauges will read from Xgauge #24 down to #0. )
FICM Vehicle Power (Volts) (Should be 12 Volts)(should not drop below 10.25 for more than 60 seconds, or 9.0 for 4 seconds. TSB 09-24-03)
FICM Logic Power (Volts) (Should be 12 volts)
FICM Main Power (Volts) (Should be 47-48) (this does work! )