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.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Siemens Engine Management System: Notes

Use the Manual With the Right Hardware

When to See a Mechanic

Rather have a pro handle this?