Siemens Engine Management System: Operation

Siemens is an engine management system which meets the needs of Low Emission Vehicle (LEV) compliancy and is also OBD II compliant. This system also includes control of the Motor-Driven Throttle Valve (MDK). The PCM uses a pc-board single-processor control unit in the new SKE housing. E-box is located next to brake master cylinder. The Siemens PCM is flash programmable as are previous systems. PCM 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.

  Special features include 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. A new PCM must be installed if necessary.