OH, great! Not too convenient to reroute my camping trip to the nearest Ford dealer and let it idle while they find time to help.
On a brighter note, I found several references to the same fault display and one guy who had his fixed. Turned out to be a temp sensor in the pan. Unfortunately, they dropped my pan and changed the filter when they did the last trans service. Hate to go back in just for a sensor. If I can find out which one and where, I might give it a go myself. After that spark plug fiasco, this should be a breeze.