Immobilization System: Function

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2004 Land Rover Discovery, 2003 Land Rover Discovery, 2002 Land Rover Range Rover, 2002 Land Rover Discovery, and 2001 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.

With the ECM operating in the NEW state, Textbook/T4 is required to instruct the ECM to learn the new BCU code. If the ECM is in delivery state (i.e. direct from the supplier), it will not run the vehicle and will store a new ECM fault code when it is fitted. This code must be cleared after instructing the ECM to learn the BCU code using Textbook/T4.

When the ECM is in the SECURE state, no further action is required as the ECM has successfully learned the BCU code. A SECURE ECM can not be configured to a NO CODE state.

If the vehicle is fitted with an ECM with a valid code, the engine will start and the MIL will go out.

However, if the ECM has an invalid BCU security code the engine will crank, start, and then immediately stall. The status of the security system can only be interrogated using Textbook/T4.

Textbook/T4 is able to retrieve the following immobilization fault codes. See Fig 1.

Fig 1: Immobilization System P Codes

Courtesy of LAND ROVER NORTH AMERICA, INC.