Hi advice needed please, jet washed engine yesterday and now has loads of faults, hdc, gearbox, etc, I've had it plugged in but it says can't read faults as no communication from the transfer case module, Changed Brake switch also today, do you think the module is shot? Tia

probably water in the tx box ecu which is behind the battery.

Remove from car and try and dry out slowly.

I have taken them off and got them drying

The green light on dash (low) went off when i took the module out and now refitted is back on and car is still the same, could it still be the module?

Sounds like it, although don't know much about them

To late now but it even states in handbook not to pressure wash under the bonnet.
Just far to much electrical boxes and connections which can't handle the pressure, or water.
You can even damage paintwork with some of these units on sale.
Plenty of products to remove grease and oil without the need for soaking everything.  John

RRS MY12 SDV6 HSE. Sumatra Black/Ebony & Walnut + Dynamic Pack, + Cold Climate Pack + Memory Pack, Digital TV/DVD, Premium Leather, Cornering Lights, Cooler/Fridge Box, & most Options.

There's probably still water sat in some of the electrics, it takes ages to evaporate out. Jet washing under the bonnet is a terrible idea, there is a reason mechanics use steam cleaners to clean engines, and even then there is a big risk to the electrics.

I think you may be chasing electrical issues for a while