Bosch DME ML 3.3 Engine ECU Repairs

Type: Bosch Engine Management
Fits: BMW 535i / 735i / 635csi
Engines: E12 / E23 / E24
Year:
Ref: ECUT319195

Note: This ECU may also fit other models.

Take the details at the head of this page on their own and the Bosch DME ML3.3 looks like a unit for three large BMWs: the 535i, 735i and 635CSi. The table further down tells a wider story. One of its four Bosch numbers belongs to those cars, while the other three are recorded in BMWs with the smaller M20 engine, which the Fits line never mentions. That gap is why the note under the details says the unit may also fit other models.

0 261 200 061: the row behind the Fits line

The one row that matches the details at the top is 0 261 200 061. Our records place it in all three of the cars they name, each running the M30 six: the E28 535i, the E23 735i and the E24 635CSi. No other number in our table is recorded against the M30.

For an owner of one of those three cars, then, the 061 row is the obvious place to start. It is still a starting point rather than a conclusion. A DME can be changed at some stage in a car’s life, and we identify the unit from the Bosch number on its case, not from the car it was fitted to.

Two rows for one car: the E30 325i

Half of the table belongs to a single car. Both 0 261 200 073 and 0 261 200 081 are recorded in the E30 325i with the M20 2.5, and both are well represented in our records for it. We hold nothing reliable that separates them by year or by version of the car, so we do not draw that line.

That makes the 325i the only car on this page where the badge leaves two numbers in play instead of one. Knowing you have a 325i tells you the pair to compare against; it cannot tell you which of the pair is in your hand. The difference sits in the last two digits, 73 against 81, so copy the whole Bosch number from the case rather than the first few groups.

0 261 200 074 and the E28 525e

The fourth row, 0 261 200 074, is recorded in the E28 525e, which runs the M20 2.7 known as the eta. Fewer sources stand behind this row than behind the other three, so we give it less weight: it is a recorded fitment, not one we would lean on without seeing the label.

It also completes the picture the Fits line leaves out. Between them, the 325i pair and the 525e row account for three of the four Bosch numbers, and none of those cars is named in the details at the top.

Why the BMW number column is blank

Every row in our table has an empty BMW part-number cell. We leave a cell empty until a BMW number has been confirmed for that specific Bosch number, and on this page none of the four has been. The Bosch number is therefore the reference we work from.

Your label may well show a BMW number alongside it. If it does, write it on your enquiry exactly as printed, character for character. It is recorded with your unit, but it plays no part in how this page identifies an ML3.3.

From arrival to return: the ML3.3 on our bench

Each unit is logged on arrival and inspected by eye before it is tested electrically. Diagnostics are then aimed at the fault you described. Nothing is sent out: our own engineers do the work in our own UK workshop, on our own equipment.

Once the cause is found, we tell you what it is and what the repair will involve, with a quote. No chargeable work starts until you have agreed to it.

The repair is made at component level: the parts on the circuit board that have failed are traced and replaced individually, under a microscope and with temperature-controlled rework equipment. The unit has to pass a final test before it leaves, it goes back to you as the same DME you sent, and the repair is covered by our 24-month warranty.

Getting your ML3.3 to us by post

We take engine ECUs in by post from anywhere in the UK. Note the Bosch number from the case, any BMW number printed beside it, the car it came from and how the engine has been behaving, then start a Repair Form for your ML3.3 and we will come back to you with the next step.

If your DME is from a BMW not covered here, look through the BMW part of our site. For a unit from another make, go to the index of every manufacturer we cover.

The four Bosch numbers are listed below as our table prints them, with the BMW column left blank for the reason given above.

Common part numbers associated with this type of unit