2005 L322 Autobiography, automatic. Currently sat on the drive in limp mode with a Trans Fail Safe error. Looking for help diagnosing the problem.

Background when it happened. When the wife (typical, I know) tried to over take a car on a carriage way, it lost power and resulted in her pulling over. Up to this point, the vehicle has been brilliant, running smoothly with no problems shifting gears. Recovery vehicle tried to drive it but only managed a few meters. Had to place the vehicle on a flat bed to get it home. It was pulled onto the flatbed when in neutral, no problem. When trying the free wheel it off it was stuck in Park. When in neutral, it can go forward but not backwards (not sure if this is a characteristic when in failsafe mode?). Managed to get it off the flat bed via youtube videos releasing the park brake under the gear shift lever

Had a friend from a local garage to take a look it a few days later and he managed to drive it a couple 100 meters and got it to shift gear. His suspicion it is an Inhibitor Switch fault. I have done some research into this to prepare what I need to do for a self replacement/repair. I have the GM type transfer box which means the inhibitor switch is within the transfer box, not outside like the ZF. I have traced back the cabling into the EAT ECU but I have no idea which terminal block is for the Inhibitor switch. What I would like to know, does anyone know how to test for the Inhibitor switch by checking the connections before I go down the road of draining the transfer box and removing the Inhibitor Switch for inspection.

Anyone else have any experience similar to this which was caused by something completely different?

I hope someone tells me this is an easy fix and will hardly cost me a thing lol.

Thanks in advance 2005 Range Rover TD6
2003 BMW 5 series E60

I must admit that I’m struggling to understand your post, but can you say if the PRND indicator on the dashboard lights up and also correctly corresponds with the position of the gearshift lever?

Click image to enlarge

Hello, apologies for not making sense, doesn't for me neither. The PRND does show on the dash when using the lever to select. I'm currently in the process of going through the switch contacts using the manual book using the table showing the inhibitor switch track. I've just confirmed the cables are ok with a loop impedance check.

Update, using the inhibitor switch track table using the Range Rover manual, all the connections seems to be working