Commodore VT engine management computers require a stream of data to be sent to them from the body control module, prior to starting the engine. This is part of the vehicles anti theft system. The stream of data required by the ECM/PCM is a special. Fortunately the input to the ECM/PCM can be switched off by changing the program information in the mem-cal. Marks 4WD Adaptors can supply mem-cals on an exchange or out right basis.