Welcome to JA.
It sounds like you may have got some water on the ecu's behind the battery. Take out the battery and take the cover off of the box behind the battery towards the firewall. The ecu you will see behind the cover is the transfer case control module. The grommets for the wiring harnesses that go into that box leak and it gets water into that module. Pull of the connectors there will be a blue, yellow, and a gray connector. See if you see any water or corrosion on the connectors if so clean the connectors an you will Below is a pic of a Range Rover sport but the module is in the same place.
I figured a short of some sort - this is not an issue of toasting the ECU is it? Once clear should I hit it with some WD 40 - or just a cloth ?
I just went out to go about it, but I am at work so will have to wait at least until lunch to do a cloth wipe.
I reconnected the baterry just now and it did not excite anything, and I locked it with the key fob and it remained locked and did not start going crazy - is it possible the water will evaporate on its own?
I am thinking that as this happened only yesterday, the chances of corrosion are small - but are you saying that if the connectors on the module itself are corroded it requires replacing the module?
You dont have to just make sure the grommets where the 2 wiring harnesses go into that box are seated correctly so no more water gets in there.
I wouldnt worry it shouldnt be that big of a deal. If you get a message in the message center that says reduced engine performance then I would take it in. As long as it is running ok then you should be good to go for right now.
P0130 is bank 1 sensor 1. Your car may need to have the software updated in the powertrain control module. If it hasnt been done in the last couple of years then this may rectify the O2 sensor fault. There are Land Rover bulletins about this code sayoing this is the fix. The only way to know if you have th latest tune is to have it checked with the diagnostic equipment at the dealer. If you want to replace it both of the front sensors are the same.