L322 Td6 hdc, air, trans

Hi everyone, just wondering if anyone has any ideas on things I can check, was driving home from a job, about 25 miles, drive there no probs, got in car about two miles into return car beeped, HDC inactive, air suspension inactive, then ten mins later trans fail safe prog, car stayed locked in road height, and gearbox behaved as normal, not locked into gear and could still use sport and manual mode aswell.
Came home, turned engine off and back on, air suspension works again and only hdc inactive remains on, when driving the trans fail safe didn’t stay on, just flashed up the once.
Iv checked a few things like brake lights work fine, I can engage high and low range, air suspension works as it should. Iv tried lock to lock steering reset with no luck, mechanic can’t get his scanner on it until end of next week but anyone any ideas of things I can physically check? Cheers.

Also had a new battery (bigger size as recommended here) in October and showing 12.8 engine off 14.3-14.9 engine on.

Quick update. Just been out and messages have gone after about 20 seconds driving. Did 6 miles and not returned so no idea if it’s a sensor breaking down or random glitch.