DME Control Unit Features

The engine functions are controlled by the DME control unit. Other measured input values, such as air volume, engine rpm, actual camshaft position (Hall sender in distributor), engine temperature, intake air temperature and throttle position, are used as data inputs for the control unit.


The main system actuators, such as the injection valves, the ignition final stages, the engine idle speed positioner, the tank vent and the resonance flap, are all controlled by the unit. The control unit is installed under the left hand seat in the car.

Features Of The DME Control Unit:

- Injection (sequential)

- Ignition (twin ignition)

- Warming up and acceleration enrichment

- Start up control

- Lambda control (adaptive)

- Overrun shutoff

- Knock regulation (selective cylinder control, adaptive)

- Anti-surging

- Torque reduction during Tiptronic gearshift accomplished by ignition retard

- Engine idle speed correlation for Tiptronic equipped vehicles

- Engine idle speed control with adaptive, automatic engine idle air correlation (system modulation)

- Carbon canister purge

- Resonance flap control

- 55-pin connector

- Diagnosis with System Tester 9288

Note: On vehicles fitted with Tiptronic, the DME control unit is coded with a special Tiptronic wire harness.

In vehicles fitted with a catalytic converter and appropriately coded DME control unit, the engine idle CO value is adapted, i.e. the control range of the oxygen sensor shifts the map to adapt it to any deviation from the specifications that may have occurred. This allows tolerances of environmental conditions (air pressure etc.) and tolerances within the engine to be compensated. Adaptation of the engine idle CO level eliminates the necessity for a basic setting.

Permanent positive at the control unit
As the DME 2.10.1. includes a number of adaptive (self-learning) systems (oxygen sensor closed loop control, charge control, knock regulation), terminal 18 on the DME plug is supplied with a permanent positive voltage. If the plug is disconnected from the control unit or the battery, the engine has to be run to operating temperature and left running for approx. 10 mins. after the next starting sequence to enable the control unit to readapt itself.

The control unit contains a volatile fault memory, i.e. all the faults stored in the memory are erased once the control unit has been disconnected from the permanent positive voltage.

Coding The Control Unit
To be able to retrieve the various maps, a 2-pin connector is branched off from the DME wire harness near the control unit connector.