Hello,
I have a several questions relating to the transfer case module on a range rover sport l320 - the one that sits behind the battery on the vehicle.

Firstly is this part sometimes referred to here as the "all Terrain programme module" ?

Secondly,Once a new part is fitted it has to be "programmed to the car - Is this something that can be done using the "GAP tool" or does it need to go into a specialist with more technical equipment ? I am the darkness before the storm

I think terrain module you mention is the Terrain Response module that sits in the centre console as part of the Terrain Response switch gear.

The transfer case module interacts with others such as the TR module, the engine ECU, etc., to decide what to do with the centre diff locking mechanism and to let the Terrain Response module know that high or low range is selected. Rock crawl, for example, requires low range so the Terrain Response module won't activate rock crawl unless the Transfer Case module confirms that low range is engaged in the transfer box. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed