BMW 745i Turbo - Motronic engine control box codes

Bosh box number: 0 261 200 013 or 0 261 200 024

We need to have certain information of your Motronic box in order to select correct computer code. For that you have to take the box out of the car and open it:

The box is located behind right front loudspeaker (picture 1). Open the cover. Note that there is next to the loudspeaker a relay (picture 2), which is connected to the Motronic wire harness. If relay's connector is loose you can not start the engine! Before you remove the box be sure that the ignition key is OFF!

The box is fastened with four screws; two on both sides (picture 3). Take the box out with the wire harness (picture 4). It is usually easiest that way. Note that the two connectors (one for engine and one for transmission) are slightly different even though you can't see it, so you will not be able to install those into wrong sockets.

Open the lid. The one to be opened is the one "MOTRONIC" label on it. There are 9 small metal clamps on the lid. Three of them on the connector side, two on each side and two on the back. Use screwdriver in order to remove the lid. Do NOT bend the clamps, just put screwdriver under the right clamp and lift it a bit. There should now be a small opening between the lid and the Motronic unit case. Put the screw driver in the middle, lift a bit and then to left and lift it then carefully on the both aside and then the lid can be taken away (picture 5).

Open the screws (four of them), remove the rubber cap in the middle of the PCB (printed circuit board) and remove the white Teflon shield.

Lift the PCB from the non-connector end a bit and push the connector so you can open the Motronic unit like a book. Those two PCBs are connected together by using a flat cable, do not damage it (picture 6).

Picture 7 is an example of a four EPROM -version of the box. During the lifetime of 3.4 L 745i (05/1983-1987) Bosh manufactured three major versions of the box with either four 2716's, two 2732's or one 2764 EPROM. In addition there were a number of software versions for each major hardware version.

First look how many EPROM's are in the top printed circuit board. All EPROM's are marked on the PCB with S72* -coding:
-        If you have four EPROM in your PCB, the one to be changed is the "S723".
-        If you have two EPROM in your PCB, the one to be changed is the "S722".
-        If you have one EPROM in your PCB, the one to be changed is the "S720".

Take down the code on the actual EPROM, As an example the code on "S723" in four EPROM version can be something like 1267355052.

Take down the Version number on the PCB (see picture 7 for exact location. E.g. in a four EPROM board it could be "FD 11.4 RU".

The PCB codes are not necessary, but may sometimes be useful information. Take those also down. E.g. in a four EPROM board those could be
1 268 329 033-5
1 268 300 067
1 268 310 033

As a summary we need following information from you:
* Number of EPROM's on the digital printed circuit board (PCB)
* Code on the EPROM
* PCB version number
* PCB codes (optional)

Click pictures!

1. Location
2. Relay
3. Box in
4. Box out
5. Cover off
6. PCB's
7. Digital PCB