Bosch DME M 1.2 Engine ECU Repairs

Type: Bosch Engine Management
Fits: BMW 750i
Engines: E32
Year: 1987 – 1990
Ref: ECUT308195

Note: This ECU may also fit other models.

A BMW 750i of the E32 series runs its M70 V12 on two engine ECUs, and the table on this page lists two Bosch numbers. It is easy to read them as that pair. They are not: on the 750i this page covers, both units carry the first number, and the second number belongs to a different BMW altogether.

Below, we take the two rows one at a time, cover what to tell us when a V12’s units travel singly or together, deal with a later 750i number that is not an M1.2 at all, and set out what happens once a unit reaches our workshop.

Row one: 0 261 200 156 and the 750i V12

The first row is the Motronic M1.2 DME for the BMW 7 Series E32 750i and 750iL with the M70 5.0-litre V12 petrol engine. Our table prints its Bosch number as 0261 200 156, and the case may show it spaced as 0 261 200 156; the two are the same reference.

Beside it, the table gives BMW’s own part number, 1725694. That pairing is consistently published against this unit, so a label showing both numbers matches the row firmly. The spec lines at the top of this page, naming the 750i and the E32, were written for this row and describe it alone.

One unit or both: what to tell us from a V12

The M70 does not rely on a single DME. It carries two of these M1.2 units, an arrangement BMW’s own technical training material describes as a dual DME set-up.

So a 750i owner has a choice to make before anything goes in the post, and we would rather be told than assume. Please say whether you are sending one unit or both, and quote the label of each separately, even where the two look identical.

You do not need to have decided which unit is at fault. Tell us what you know and how the car was behaving, and we will work from there.

Row two: 0 261 200 350 and the E34 M5

The second row is also a Motronic M1.2 DME, but from a different car: the BMW M5 of the E34 series, with the S38 3.6-litre six-cylinder petrol engine. It is not a 750i unit, and it is not the other half of the V12’s pair.

If you own an E34 M5, the second row is yours, even though the spec lines above mention only the 750i. Quote the Bosch number and any BMW number exactly as they appear on your own label. For the BMW number in particular, go by your unit rather than by anything printed on this page; the label is what our engineers check against.

Both rows carry the Motronic M1.2 name, one built for a twelve-cylinder engine and the other for a six. The name is shared; the unit is not, and the Bosch number is what separates them.

When a later 750i label reads 0 261 200 352

Not every 750i carries the M1.2. The later, facelifted 750i moved to a different unit, Bosch 0 261 200 352, which is a Motronic M1.7 and is not listed on this page.

If that is the number on your label, send the unit to us through the Repair Form all the same, quoting it as printed. Our technical team confirms coverage for a specific unit rather than guessing. You can also look through BMW engine ECUs that are not M1.2, and for a unit from any other manufacturer, the list that starts from the badge on the bonnet is the place to begin.

What happens once your M1.2 DME arrives

Every unit is repaired in-house by our own engineers, in our own UK workshop, on our own equipment. On arrival it is logged, inspected and tested electrically, then taken through diagnostics aimed at the fault you describe.

We then contact you with the outcome and a quote, and no chargeable work begins until you authorise it.

The repair itself is carried out at component level, under a microscope with temperature-controlled rework equipment, so it deals with the part that has failed rather than replacing the whole DME. A unit is not finished until it passes final testing, and the specific repair is covered by our 24-month warranty.

We work by post across the whole of the UK. Whichever car the unit came from, give us the Bosch number, any BMW number from the label, the model and a line on the fault; if it came from a 750i, say on the Repair Form whether one or both are coming.

The two Bosch M1.2 numbers covered on this page are listed below.

Common part numbers associated with this type of unit