Removal Precautions For Electronic Control Units

Comply with the following when replacing the DME (Digital Motor Electronics):

1. Always read out hardware/software version of the corresponding control unit with DIS tester.
2. Comply with the instructions of the DIS tester on the steps coding and programming.
3. On vehicles with electronic vehicle immobilization, comply with the instructions of the DIS tester.
4. Each control unit is programmed with certain basic values, which serve as mean values. The control unit receives different input values, depending on engine condition, which are compared with the stored values. The adaptive system compares the input values with the stored map values. The control commands are routed to the relevant actuators.
5. If, for example, the DME control unit were without correct for a long time (more than an hour), its adaptive system would lose the stored values. When a cleared control unit is restarted or a new control unit is installed, the adaptive system must read in and store the input values of the associated engine as new basic values itself.
6. This procedure could lead to erratic idling and disturbed overrunning of the engine after starting. Depending on the engine it could require some time before all values are adapted to the engine condition.
7. Therefore observe the following procedure before replacing or reinstalling a DME control unit:
   • If possible before exchanging control unit, run engine up to operating temperature.
   • Remove the control unit, install a new control unit and operate vehicle at different engine speeds.