Bosch DME M 1.3 Engine ECU Repairs

Type: Bosch Engine Management
Fits: BMW 316i / 318i / 320i / 325i / 325is / 520i / 525i / 730i / 735i
Engines: E30 / E32 / E34
Year: 1988 – 1994
Ref: ECUT309195

Note: This ECU may also fit other models.

On this page, a BMW 320i has more in common with a 520i than with a 325i. The 320i and 520i are different bodies around the same 2.0-litre version of the M20 six, and their Motronic M1.3 DMEs are recorded against the same Bosch numbers. The 320i and 325i share an E30 body and sit on different ones.

That comparison is the key to the eleven references listed here. Read the badge past its first digit: what follows tracks the engine, and the engine decides which small group of rows to look in. The sections below take the three families in turn.

Why the end of the badge matters more than the start

On the cars this page covers, the first digit of the badge names the body: 3 for the E30, 5 for the E34, 6 for the E24 and 7 for the E32. The two digits after it follow the engine. Here, 16 and 18 mean the four-cylinder M40; 20 and 25 the 2.0 and 2.5 versions of the M20 six; 30 and 35 the 3.0 and 3.5 versions of the larger M30 six.

All eleven Bosch numbers begin 0 261 200, so the last three digits do the identifying. Our table prints them as 0261 200 157 and so on; on the case, the same reference may be spaced 0 261 200 157. In our table, each Bosch number sits beside BMW’s own seven-digit part number; copy both from the label.

Four-cylinder M40 rows: the 316i, 318i and 518i

Five of the eleven rows belong to the M40 four-cylinder. The E30 316i is documented against two of them: 0 261 200 174 with BMW number 1734179, and 0 261 200 989 with 1739035. The E30 318i is documented against two more: 0 261 200 157 with 1727678, and 0 261 200 387 with 1727679.

The fifth, 0 261 200 386 with BMW number 1727674, is documented against the E34 518i. Here the pattern bends: among the four-cylinder cars, the 5 Series has a row of its own.

Look closely at 1727678, 1727679 and 1727674. The three BMW numbers differ only in their final digit, and each sits beside a different Bosch number, so a label read in a hurry can send you to the wrong row. Copy all seven digits.

M20 six: 2.0 and 2.5 cars on separate numbers

Four rows belong to the M20 six-cylinder, and they divide by capacity. The 320i and 520i are documented against 0 261 200 172 with BMW number 1730573, and 0 261 200 381 with 1730574. The 325i and 525i are documented against 0 261 200 173 with 1730575, and 0 261 200 380 with 1730576; the first of that pair is also recorded against the 325ix.

Here the badge leads to a pair of rows, not one. Each capacity has two references, and the model alone does not show which of the two was fitted; the label on the case does.

The four BMW numbers run in sequence from 1730573 to 1730576. In our table, the two ending 3 and 4 sit with the 2.0 cars and the two ending 5 and 6 with the 2.5 cars, a useful cross-check on capacity.

M30 six: one row for the 3.0, one for the 3.5

The last two rows belong to the larger M30 six. Bosch 0 261 200 178, with BMW number 1726684, is documented against the E32 730i and the E34 530i. Bosch 0 261 200 179, with 1722611, is documented against the E34 535i, the E32 735i and the E24 635CSi.

A 530i and a 730i come from different series but share a 3.0 engine and a row; a 530i and a 535i share an E34 body and do not. Three body series meet on the 3.5 row alone.

Cars our spec lines do not name

The Fits line at the top of this page lists nine models, and the Engines line gives E30, E32 and E34. The table reaches further than both. The 518i, 530i and 535i are covered by rows described above, and so is the 635CSi, from the E24 series the Engines line leaves out.

If your car is one of these, or a 325ix, you are on the right page. The Note line beneath the spec block says this unit may fit other models, and these five are documented against rows in our table. For anything else, our technical team confirms coverage for the specific unit rather than guessing.

From your label to our workbench

Every M1.3 sent to us is repaired in-house by our own engineers, in our own UK workshop, on our own equipment. It is logged on arrival, inspected, tested electrically and then taken through diagnostics aimed at the fault you have described.

When we know what has failed, we contact you with the outcome and a quote, and nothing chargeable starts until you give the go-ahead. The work itself is done at component level, under a microscope with temperature-controlled rework equipment, so the repair targets the failed part rather than the whole DME.

A repair is not complete until the unit passes final testing, and the specific repair is covered by our 24-month warranty. We work by post across the UK, so before anything is packed, list the badge and both label numbers on the Repair Form, with a line on how the car behaves.

If the unit on your bench turns out not to be an M1.3, BMW engine ECUs carrying a different designation have pages of their own, and engine ECU repair for anything that is not a BMW begins from the main list.

The eleven Bosch M1.3 references, each with its BMW number, are listed below.

Common part numbers associated with this type of unit