Well, somehow I bumbled my way to success, though I can't be sure of what exactly worked. Based on DakotaTravlr's advice, I first went into the suspension test mode and set it to normal tolerance, though I have absolutely no idea of whether it was on tight or normal when I did so (it's not a toggle between the two settings but rather two "on" switches). Light was still on and I then started another guided calibration. Half way through my phone froze up for unknown reasons and I had a work call I needed to make, so I turned off the engine, rebooted my phone, did the call, and returned an hour later. Redid the "set to normal tolerance" setting with the engine running and then did another guided calibration. When I got back into the truck I was shocked to see that the red light was now off and a scan from the tool showed no faults from the suspension system. The big question was when the light went off (after the first change to normal tolerance? After the aborted calibration? After the second normal tolerance reset? Or only after the last calibration?). Not knowing is a sign that I failed as a good researcher, but I'm not going to complain, Just to be sure, I went through the engine cycle\tolerance reset\guided calibration one more time for grins and giggles, and to my relief, the light remained off and there were no suspension faults. If it happens again I'll check the sensors, but right now I ain't touching nuthin'.

There is no happier man in California right now. Thanks to all who provided such excellent guidance...

Nick in Palm Springs

 

Awesome. Thanks for the update!

 

the red suspension light is normally associated with manufacturing calibration system set up, as it did it to my 06 disco 3,
it's where the system has been set to calibration mode or it independently switched over from normal tolerance to tight tolerance set up,
which can happen if front or back have been raised or lowered for a period of time, as my rear valve block leaked over night and triggered
manufacturing calibration. easy fix is just to switch the settings over on a gap tool or dii.

 

Follow-up: My light never came back on and the fault never showed up again in the two years since that little episode.

Nick in Palm Springs

 

So much wrong with this... .First there are numerous faults that can cause a red dash light. A having it raised or lowered for a period of time would not cause a calibration issue......