2011 LR4 spare tire low pressure warning light

So this annoyance is very Saab-esque in nature:

3 weeks ago had to put the spare tire on due to a slow puncture in my left front. Upon extracting it from beneath the back of the car it only had 20lbs of pressure in it (not unexpected).

After I got the regular tire/wheel put back on, I found the sodding spare tire winch would not retract. I ordered a new one (non-OEM), which I fitted and now the spare tire is back where it should be. Since then (couple of weeks) I have been getting a "spare tire low pressure' warning light coming on. Initially constantly, but now just for the first 15 sec after start up.

Question - where the heck is the sensor that is triggering this. It ain't in the spare tire that's for sure?? Also, no warning light when the spare tire was low in pressure, but now I get the warning when it is back to correct pressure?

Any thoughts appreciated!

I had this error message with my LR3 when one of my main 4 wheels had a hairline crack in the TPMS sensor. It would be random, sometimes many times a day and sometimes it would not do it for weeks on end. In the end, it was a front wheel sensor and not the spare, even though the spare was in the fault codes.

My guess is that perhaps the TPMS in your repaired wheel may be the issue. If it is original, it probably is getting to that age where things weaken and the unmouting and re-mounting may have been the last straw.

About a year after fixing the one causing this issue, the message popped up again for me and rather than try to guess which wheel was actually having issues, I turned off the TPMS system using an IIDTool.