System Overview

Digital Motor Electronics (DME M1.7, 12-cylinder M 70):

DME And EML Diagram:

Compound System of Signals to the Drive Control Units:

Explanation of Abbreviations and Signals:

NOTES: The following description refers to the digital motor electronics DME M1.7 for the 12-cylinder M 70 engine (5.0 I).


Modifications:

Modifications:

Modifications compared to the previous digital motor electronics system 1.2, 12-cylinder M 70 (see image above).

Functional Description:

Two DME control units operate independently, each with six cylinders. If not otherwise specified, the explanations, therefore, refer to only one row of cylinders.

The DME control unit I supplies the cylinders 1...6, and the identical control unit II supplies the cylinders 7...12. To differentiate between them for diagnosis, Pin 40 of the control unit II is connected to ground. The associated components are mainly provided double. Exceptions are:

- Relay for oxygen sensor heating and
- Engine temperature sensor.

The oxygen sensor heating relay is assigned to the control unit I. The two engine temperature sensors are mounted together in one housing.

The DME system makes it possible to precisely control fuel injection and ignition under variable operating conditions.

The system can also operate in conjunction with other systems such as:

- Electronic transmission control EGS
- Electronic throttle control EML
- Automatic stability control ASC
- Engine drag torque control MSR
- Instrument cluster
- Antitheft system DWA
- On-board computer BC

The DME system assumes functions which are listed briefly below and are described in more detail in Functional Descriptions.
Functional Descriptions

- Injection control
- Ignition timing control
- Cold start control
- Engine speed control
- Acceleration enrichment
- Dynamic torque deceleration fuel cut-out
- Catalytic converter protection function (ignition circuit monitoring)
- Adaptive emission (lambda) control
- Adaptive fuel evaporation control
- Intervention in ignition and injection with ASC or MSR active
- Characteristic map switchover for EH transmission
- Relay control
- NC compressor cut-out
- Self-diagnosis with defect code storage

Input Signals:

Input Signals:

Input Signals:

Output Signals:

Output Signals: