System Components: Notes

MED 9.2.1 Engine Control Modules - New Features:  This Bosch Engine Management System is introduced for more stringent emission requirements as well as reducing fuel consumption and increasing driving performance. Flash EEPROMs (additional 1 MB flash memory) are used as the storage medium for program data, fault code memory as well as the adaptation values.

The 134 pin MED 9.2.1ECMs are manufactured by Bosch to BMW specifications. The ECM is the SKE (standard shell construction) housing and uses 5 modular connectors.

For testing, use the Universal Adapter Set (break-out box) Special Tool: # 90 88 6 121 300 

The ECMs work in combination with the Valvetronic Control Module. The N73 engine has a total of 5 control modules to manage the engine functions:

Fig 1: Identifying MED 9.2.1 Engine Control Modules

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Identifying Valvetronic Control Module

Courtesy of BMW OF NORTH AMERICA, INC.

1. MED 9.2.1 ECM 2 - overall engine management
2. MED 9.2.1 ECM 1 - overall engine management
3. Valvetronic Control Module - intake valve lift
4. High pressure fuel injector control module (HDEV) - activates injector group for one bank
5. High pressure fuel injector control module (HDEV) - activates injector group for one bank

These modules are located in the electronic box in the engine compartment together with the Integrated Voltage Supply Module (6).

The ECM controls an electric cooling fan in the base of the electronic box to draw in cool air from the passenger compartment.

Fig 3: Identifying Integrated Voltage Supply Module Bus

Courtesy of BMW OF NORTH AMERICA, INC.