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Rover 400 MEMS

MEMS vs OBD II

The Rover MEMS (Modular Engine Management System) was fitted to Rover Cars and Land Rover vehicles. In general until 1996 the units were of Lucas 14CUX, 4CU and 13CU or Rover origin, controling primary ignition, fuelling and idle functions.

The Rover MEMS has diagnostic functions, the Lucas 4CU does not, The Lucas 13CU was only fitted to a limited number of export vehicles. The MEMS modules continually examines signals engine sensors, each signal is compared to recorded pre-programmed values and limits if the system determines that the sinals fall outside of the limits one or more fault codes ore stored. Codes are only stored for a limited range of engine components. The Rover MEMS does not generate fault code numbers like the current OBDII systems, fault information can be retrieved using the Rover T4 diagnostic equipment or similar third party readers.

The original Lucas hand held fault readers required an interface unit, and firmware package which framed packets according to ISO 9141 communications protocol (ISO 9141-2 is the current OBDii). It also used seperate modules for use on brake systems etc.

Rover's version of the reader 'Test Book' (T4) was provided to Rover franchised dealers only. Although it is available secon hand now the software is not useable on computer systems using NTFS file systems. The equipment also requires a Serial port as an interface.


Retrieving fault codes


The only method of retrieving fault information from Lucas 14CUX and Rover MEMS is by use of T4 or similar dedicated Fault Code Reader.


Clearing fault codes


The only method of clearing fault codes from Lucas 14CUX and the Rover MEMS is by use of T4 or similar dedicated Fault Code Reader. In particular the Rover MEMS employs non-volatile memory, and codes will remain stored even with the battery disconnected.

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