Attention: Each control unit is programmed with certain basic parameters which only represent average values. The control unit, depending on the state of the engine, receives from the sensors various input values, which are compared with the accumulated values. After that, the control unit changes the commands and execution accordingly. New values of quantities are accumulated, and thus the current process called "learning".
If the DME control unit has been without power for more than one hour (unit removed or battery disconnected), then its self-learning system loses the accumulated values.
When commissioning a control unit with erased value values or when installing a new unit, the system must again accumulate the value values. This process after starting the engine can lead to erratic operation of the engine not idling and malfunctions during operation in the forced idling mode. It is necessary to drive the car for several minutes at a variable speed until all the values characterizing the state of the engine are aligned.
After installing a new control unit in a workshop for BMW vehicles, it must be entered with the vehicle code and programmed. This requires a device that allows you to perform diagnostics and data entry. If possible, warm up the engine while driving with the old control unit, and then install a new control unit when the engine is warm. This allows you to speed up the process of adapting the new control unit to operating conditions.
Withdrawal
Before removing the control unit, it is recommended that a BMW workshop read and print out the information from the fault code memory. Thanks to this, it is possible to determine what faults exist, see also.
Disconnect ground wire (-) battery. The battery is located in the engine compartment behind the right side trim.
Attention: Read the instructions from the chapter "Removing and installing the battery".
To gain access to the electronics unit, remove the microfilter box in the rear right of the engine compartment to clean the air in the passenger compartment.
Release screws -1- and remove fuse box cover.
1 - control unit of the DME system;
2 - shaft for the automatic transmission control unit (where available).
Release the retaining clip of the plug connector and disconnect the connector.
Pull the control box out of the retaining clips. It is not necessary to loosen the clamp bolts.
Note: With an automatic transmission, the second control unit is located next to the DME control unit.
Installation
When buying a replacement block, the number and coding of the block are indicated. To identify the part, it is advisable to take the removed block with you.
Insert the control unit, connect the plug-in connector and secure it with the clip.
Replace cover.
Install the battery.
If the control unit has been de-energized for more than one hour or if a new unit has been installed: Warm up the engine to operating temperature. Carry out a test drive for approximately 10 minutes at various speeds. At the same time, the control unit "studies" engine parameters.