Disco 2 three amigos, where to start?

Hello
After some major overhoul on my car (T-box seals, gearbox seals, main shaft seal, clutch) the 3 amigos have showed up already a few times. I finished my car about 2 weeks ago and the first way out from my garage started with 3 amigos warning. I connected Nanocom, red the alarm (shuttle valve switch electrical fail) and deleted it. The car was fine after for about 300kms. Yesterday when TC has activated due to slippery road I got again the 3 signs! After deleting it come back again (same error code).
Is there any possibility that during removing and installing gearbox and T-box something has damaged which has coused the problem, or possibly there is no connection (I have never had this issue before this repair)?
Should I check some other things before I start directly with this shuttle valve switch?
Thanks

"Shuttle valve electrical fail" is usually a fault with the connector inside the ABS modulator. It's often not necessary to even replace the shuttle valve switch plate, although it might be a reasonable idea to do so.
Step by step instructions are shown in the "Option B" attachment on how to test the switch plate and how to install the modification. You can find these in message #3 in the "shuttle" thread:-
https://www.landyzone.co.uk/land-rover/shuttle-valve.327531/
There are a number of videos on Youtube about this modification, but the instructions given in the Option "B" file is probably the best set of instructions.
There's no need to remove or dismantle the ABS modulator other than removing the switch plate and the whole mod should take no more than about two hours.

There's an even better fix described by Fery on the D2 boys' club. Look for non-invasive shuttle switch.

I did mine about 3 years ago and absolutely no problems since. TC, ABS HDC and everything else all working perfectly.

Thanks for the advices! I will doublecheck all connections and if the problem comes back i will do the mod.