LUCAS GEMS

A cooperation between Lucas and Sagem produced the GEMS which can be found fitted to the petrol versions of the P38 from introduction until the 1999 facelift. It can also be found in NAS specification Defenders and Discoveries as well as the 50th anniversary edition Defender.

The GEMS is a very sophisticated system using feedback from many sensors to self compensate for wear, tolerance, climate, etc., thus helping it maintain the same running standards to which it was designed. The system also has an equally sophisticated self-diagnostic system and can self detect up to approximately 1000 different faults, ranging from very bad ones causing the engine to not start, through to logging slightly abnormal events in the normal course of vehicle usage which don't even create a warning. Sometimes multiple faults may be logged which may have been caused by the same faulty component but in this event they will all share a common thread which can help to locate the faulty part. Under certain fault conditions, the ECU stores freeze frame data. The ECU will store only one freeze frame data at the time. If another malfunction that has freeze frame data occurs, any freeze frame data stored previously will be replaced by the new conditions.