Royal, If you havent done this already.
You need to splice the wire from your o2 connector, and run wire from it to the back of your ICCU. It tells you what type of wire is recommended in the ICCU instructions.
Or the easier way is to get one of these:
http://www.zzperformance.com/zzp/products/...uel_pigtail.htm
Casper's has these also I believe, if you want to pick one up...
The FAT display comes on the ICCU when your O2 voltage goes over 1,000mv or its not connected at all. I saw this on my ICCU and just went into the debug mode and removed the O2 display until I can get my A/F pigtail connected...
Thanks.