Siemens Engine Management System: Notes

This Siemens system is designated as MS42.0.

Siemens MS42.0 was developed to meet the needs of Low Emission Vehicle (LEV) compliancy and OBD II. This system also includes control of the Motor-driven Throttle Valve (MDK).

The ECM uses a pc-board single-processor control unit in the new SKE housing. Mounted in the E-Box (next to brake master cylinder). The MS 42.0 ECM is flash programmable as seen with previous systems.

Fig 1: Locating ECM

Courtesy of BMW OF NORTH AMERICA, INC.

ECM hardware includes:

Modular plug connectors featuring 5 connectors in the SKE housing with 134 pins.

• Connector 1 = Supply voltages and grounds
• Connector 2 = Peripheral signals (oxygen sensors, CAN, etc.)
• Connector 3 = Engine signals
• Connector 4 = Vehicle signals
• Connector 5 = Ignition signals
  Fig 2: Identifying ECM Modular Plug Connectors

  Courtesy of BMW OF NORTH AMERICA, INC.

Special features:

• Flash EPROM which is adaptable to several M52 LEV engines and has the capability to be programmed up to 13 times
• Once a control unit is installed and coded to a vehicle it cannot be swapped with another vehicle for diagnosing or replacement (because of EWS 3.3). A new ECM must be installed if necessary.