Unfortunately there is no solution to date for this problem other than replacement of the entire Steering Column. Below is a description of the information I have gathered.

The symptom that the user experiences is when the key is inserted, the key is not allowed to turn. Thus preventing the user from starting the vehicle.

The Steering Column Interlock is a very complex mechanism. Modern vehicles have a steering column interlock that locks the wheel from moving while the vehicle is off. Most vehicles have the key in the steering column. This allows a direct physical connection between the key and the steering column lock. The Range Rover has the key located in a different location. This creates the need to have a physical lock mechanism in the steering column. A separate locking mechanism that locks and unlocks depending on the status of the vehicle key creates a unique set of problems.

Because there is a danger that the steering column could lock accidentally while driving, the mechanism has several safety interlocks. There is a position sensor on the interlock servo mechanism and there is a position sensor on a locking solenoid. The two physical devices work together. If the sensor data does not agree, then the system locks down the steering wheel.

The symptom that the user experiences is when the key is inserted, the key is not allowed to turn. Thus preventing the user from starting the vehicle.

The steering column interlock ECU and the key cylinder and the vehicle immobilizer all talk to each other in the first 100ms as the vehicle key approaches the ignition cylinder. If the steering column interlock is in an error state, the key is not allowed to turn and start the vehicle. This prevents the user from ever having a locked steering column and running engine.

A power cycle of the Steering Column Interlock ECU resets this lock down for one cycle. Usually the servo motor fails or the sensor in the solenoid fails. There are no replacement parts. I have checked with the original company manufacturers.

The Steering Column Interlock ECU and mechanism are extremely difficult to gain access to. There are blind roll pins that lock the assembly into the steering column assembly. To gain access, the roll pins must be drilled out and the metal enclosure opened up.