UG reads like I don't have DFCO, and some other UG questions
 

I just set up an UG in the Corolla last Monday, and when I am coasting in gear (which I avoid as much as possible), the UG reports MPG readings in the hundreds, but not the 999.9 MPG that I would expect to see. This has been the case all the way from 3k to 1.1k RPM, so it's not like DFCO is just kicking in at certain RPM ranges. Any idea what's going on? The Corolla should have DFCO...right?

Also, sometimes when I turn the key into accessory when pulling into a parking spot, the UG will read 999.9 MPG; other times, it read 00.0 MPG. I can't figure out what is causing the different readings.

Are you using the 8 gauge per page display? I only see DFCO dispalyed when using the 4 or 6 gauge per page display. When on 8 guage mode, I see exactly what you are describing.

If not there is an adjustment for DFCO detection that may need to be dialed in. Forget what it is called but can check when I get home tonight.

My dad has an 04 Corolla LE auto and it doesn't have DFCO. At least if it does, I couldn't feel it.

Are you sure you turned on the DFCO function on the UG? I had to turn it on and enter some basic engine info, I think.

You gotta see the number to 7x the engine size.

A quick way to check if you're in DFCO with a manual tranny is to turn off the ignition while coasting in gear. If the rate of deceleration stays the same, you were in DFCO. If it increases, you weren't.

I got the ScanGuage first and got used to it in my TDi. I picked up an Ultraguage and have been disappointed. Evidently it will not show DFCO in a diesel at all and the instant mpg was way off when I calibrated according to the manual for my Grand Cherokee CRD. I had to set the engine size to 1.1 liter to get it close. I should have spent a little more and gotten another ScanGuage, especially in the diesel. More user friendly too IMHO.

I thought all 9th generation Corollas had DFCO. But then again drive by wire wasn't incorporated until 2005, so maybe not??

My car doesn't have DCFO Its not on every vehicle.

If you have DFCO, the easiest way to tell is to watch you open loop/closed loop display. Open loop while decelerating means DFCO, even if the gauge is still reading normal MPG. You can then fine tune the gauge to read correctly (usually).