Bosch DME ML 3.1 Engine ECU Repairs

Type: Bosch Engine Management
Fits: BMW M3
Engines:
Year: 1987 – 1990
Ref: ECUT318195

Note: This ECU may also fit other models.

Every Bosch DME ML3.1 we have on record came out of one car, the E30 BMW M3, and yet it turns up under two Bosch numbers. Which of the two is in front of you depends on when that M3 was built, not which M3 it is, and the place to read that difference is the label on the unit’s case.

The only car on this page: the E30 M3

Most of our BMW DME pages have to sort one model from another before the label comes into it. This page has a single model to deal with: the E30 M3, running the S14 2.3 four-cylinder. Both Bosch numbers in our table, 0 261 200 071 and 0 261 200 091, are recorded against that car and that engine, and both are well documented against it.

The Engines line in the details at the top is empty, but the engine is not in doubt: it is the S14 for both entries. With car and engine settled, what remains is which of the two numbers your M3 was built with, and whether that unit is still the one fitted.

Earlier and later: how the two numbers divide the M3’s production

Period listings for the M3 put the two units in sequence. 0 261 200 071 is the earlier fitment; 0 261 200 091 took over on later cars. The body, the engine and the badge stayed the same, and the Bosch unit supplied for them changed.

The ML3.1 name is most often recorded against the later number, 0 261 200 091. The earlier 071 sits on the same page because it served the same car and the same engine, and for identifying a unit it is the Bosch number that counts rather than the name.

Why the M3 badge cannot choose between them

On many BMW pages the badge does real sorting work, because different models ran different units. Here every car wears the same M3 badge over the same S14 engine, whichever Bosch number it was built with. The badge answers which car; the question on this page is when.

Knowing roughly where your car sits among earlier and later M3s tilts the odds towards one number. It cannot settle the matter, because a car of this age may no longer carry the DME it was built with, and a unit bought loose may have no car attached to it at all. Either way, the label is the record that stays with the unit.

Reading the label when the BMW column is empty

Our table for this unit has two rows, and the BMW part-number column is empty in both. That is intentional. A BMW number is added to a row only after it has been confirmed for that exact Bosch number, and neither row has reached that point.

The Bosch number therefore carries the identification on its own. The table prints the pair as 0261 200 071 and 0261 200 091, and they share every digit except one: a 7 on the earlier unit where the later one has a 9. Copy the number from your label as it reads, and that single digit tells us which of the two you have.

If the label also carries a BMW number, send that too, exactly as printed. It goes on the record for your unit, even though the ML3.1 is identified by its Bosch number.

What happens to an M3 DME in our workshop

We book the unit in against the details on your form, look it over, and test it electrically before running diagnostics aimed at the fault you described. The work is done in-house, by our own engineers, in our own UK workshop.

When the cause is clear, we contact you with what we found and a quote for the repair. Nothing chargeable is done until you have said yes.

The repair itself is made at component level. Failed parts on the circuit board are traced and replaced one by one, under a microscope, with temperature-controlled rework equipment. The DME must pass a final test before it is packed, and the repair carries our 24-month warranty. The unit that comes back is the one you sent.

Posting an ML3.1 to us

Engine ECUs come to us by post from anywhere in the UK. Once you have the Bosch number, a short description of how the engine is behaving and, if you know it, whether the car is an earlier or later M3, log your M3’s DME with us through the Repair Form and we will reply with the next step.

A DME from a different BMW is covered under BMW DMEs from models other than the E30 M3. For a unit from a different manufacturer, start from our engine ECU repairs for other car makers.

Check the number on your label against the two rows below before you post anything.

Common part numbers associated with this type of unit