DME Control Unit Removal and Installation

* Each control module is programmed with specific values. Depending on engine operating condition, the control module receives various data from the sensors. These values are compared with the values stored in the module memory. Based on the comparison, the control module outputs the corresponding control commands. New values can be entered into the module, i.e. it can be "adapted".
If the control module has been without power for more than one hour (disconnected or battery disconnected), the data obtained through adaptation is lost.

When the module is re-commissioned or a new module is installed in the system, new data must be entered. After start-up, this process may result in unstable engine operation and disturbances during overrun (coasting) driving. Drive the vehicle for several minutes with varying speeds so that all values in the module are adjusted to the engine condition.

After installing a new control module, it must be coded and programmed, which is performed by BMW. A special diagnostic/programming tool is required for this. If possible, drive the vehicle with the old control module and then install the new module with the engine at operating temperature. This speeds up the adaptation process.

REMOVAL
1. Before removing the control module, it is recommended to read out the fault memory at a BMW service center. This allows faults to be identified. Refer to the Fault Memory section.
2. Disconnect the negative battery cable. The battery is located in the luggage compartment behind the right side trim.

* Observe the instructions in the section Battery Removal and Installation.

3. Remove the filter box in the engine compartment at the rear right to gain access to the electronics box. Refer to the section Wiper Drive/Cover Removal and Installation.
4. Unscrew the mounting bolts and disconnect the cover from the fuse box.

5. Disconnect the plug connection by opening the clamp. Refer to the accompanying illustration.

1 — DME control module;
2 — automatic transmission control module shaft

6. Remove the control module from the clips. Do not unscrew the mounting bolts of the clips.

* On vehicles with AT, there is another module near the DME control module.

INSTALLATION

1. When purchasing a new control module, the number and coding of the old one must be known. It is recommended to take the old module with you for this purpose.
2. Insert the control module and connect the plug connection. Close the connector lock.
3. Install the covers.
4. Install the battery.
5. If the control module has been de-energized for more than one hour or a new control module is installed: Warm up the engine to operating temperature. Drive for approximately 10 minutes with varying speeds. During this process the control module will receive the necessary data.