DME control unit — removal and installation (BMW 7 Series E32)

Note: Each control unit is programmed with certain basic values, which correspond to the average values of the variables. During operation, the control unit receives, depending on the state and operating mode of the engine, various input data from the sensor, which are compared with the values in the memory. The control unit then changes the commands to the actuators accordingly. New values are entered into the memory, i.e. the so-called "learning" process occurs.

If the DME control unit has not been supplied with voltage for more than one hour (the unit was removed or the battery was disconnected), then the stored values are erased from the memory of the self-learning system.

When re-enabling a control unit with erased memory or when installing a new one, the engine input parameters must be re-entered into the system. This process can lead to uneven idle operation and interruptions during engine braking after starting the engine. The car must be driven for several minutes at various speeds until all the values characterizing the engine condition are entered into the control unit memory. After installing a new control unit, it must be coded and programmed on the car in a specialized workshop. A diagnostic unit is required for this (motor starter). If possible, warm up the engine with the old control unit and then install the new control unit on the new engine. This will speed up the break-in process.

Removal

Before removing the control unit, it is recommended to interrogate the self-diagnostic unit in a workshop to determine what faults there are.



Disconnect the negative cable from the battery.

Remove the cabin air filter. It is located in the rear right side of the engine compartment. This is necessary to access the electronic unit.

Remove the screws and remove the fuse box cover.

Pry up the fastening clips on the connector plug and remove the plug.

Pull the control unit out of the mounting brackets. There is no need to unscrew the mounting screws.

Please note: On models with automatic transmission, there is a second control unit next to the DME control unit.

Installation

When buying a new unit, you need to write down the number of the old unit and its coding. To avoid errors, you need to take the old unit with you.

Insert the control unit, connect the plug. Fasten the brackets.

Install the covers.

Connect the wire to the battery.

If the control unit has been disconnected from the power supply for more than one hour or if it is new: warm up the engine to operating temperature. Make a 10-minute test drive at different speeds. This will cause the control unit to undergo a "learning" process.