VW / Audi / Seat / Skoda (VAG) Bosch MA1.3 Engine ECU Repairs

Type: Bosch Engine Management
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT193195

Note: This ECU may also fit other models.

These six references are rarely printed one at a time. Used-parts catalogues and ECU dealers write them as 0 261 203 314/315, 0 261 203 456/457 and 0 261 203 897/898 — two references, one slash, one control unit.

The slash is the trade’s own shorthand, not something read off this page: the six numbers here are three units. What each of the three is documented against is set out below, and one of them does not behave like the other two.

One slash, two references, one control unit

Each of the three pairs is written that way by records with no connection to one another — different sellers, in different countries, giving both numbers against a single item. That is what makes the notation worth relying on: it is not one catalogue’s house style, it is how the trade files these units.

The consequence for anyone holding one of these units is small and worth having. If the number on the case is 0261203315, 0261203457 or 0261203898, it is the second half of a pair rather than a reference on its own, and the Volkswagen Group number belongs to the pair. Quote both halves and the question does not arise.

The 314/315 pair: Volkswagen Golf III 1.6

0261203314 and 0261203315 are one unit, documented against the Volkswagen Group number 032 906 026 D. Every unconnected record that names a car for it names the Volkswagen Golf III, with the 1.6-litre petrol engine.

Several of those records file the pair under the MA1.3 designation by name, which is useful confirmation if you are working from a label rather than a list. For this unit the designation, the Bosch pair and the Volkswagen Group number all point the same way.

The attribution is to the 1.6-litre petrol car specifically, not to the model line as a whole — the records name an engine as well as a model, and both halves matter. What settles the unit in the end is the reference on the case rather than the badge on the boot.

The 897/898 pair: Volkswagen Polo 1.6 AEA

0261203897 and 0261203898 are one unit against the Volkswagen Group number 032 906 026 H. The car is the Volkswagen Polo with the 1.6-litre petrol engine, and two records that have nothing to do with each other name the engine code as AEA.

This is the best-attested of the three. Used-parts records, ECU dealers and breakers in several countries give the same combination of Bosch pair, Volkswagen Group number and car, and none of them puts it on a different model. Where a record disagrees at all it is on the engine size, and it stands alone against the rest.

The 456/457 pair: two Volkswagen Group numbers

The middle pair is the one to slow down on. 0261203456 and 0261203457 are documented against 030 906 026 E, on a Volkswagen Polo with the 1.3-litre petrol engine, engine code ADX; unconnected records in several countries give that combination and two of them name the code.

The same two Bosch references are also published against a second Volkswagen Group number, 030 906 026 AJ. That is not an alternative to choose between. Both references are printed against this pair by sources with no connection to each other, and nothing in the public record explains the difference between them. We are not going to invent an explanation for it.

What the records do agree on is the car: the AJ is a Polo as well. What they do not agree on is its engine, and nothing else in the record settles that. So on this pair the vehicle-manufacturer number is the half of the identification that can let you down — a supplier holding the unit under 030 906 026 E will not find it under AJ, or the other way round — while the two Bosch references are what every record has in common.

That is true of this pair and not of the other two, where one Volkswagen Group number is agreed throughout. The same six references contain both behaviours, which is the reason to read the whole label rather than the part of it you recognise.

Reading the unit rather than the list

Four things settle a Bosch MA1.3 without guesswork: both Bosch references from the case, the Volkswagen Group number, the model, and the engine — capacity and code, if the car’s paperwork gives one. On two of the three pairs here the numbers alone are enough. On 0261203456/457 the engine is what resolves what the catalogues will not.

Check the designation on the label while you are there: MA1.2.3 and MA1.3 are close enough in print to be misread on a dirty case, and they are different units. If yours reads MA1.2.3, MA1.2.3 has its own set of references on this site.

Every reference on this page is documented against a Volkswagen. If the car is a Volkswagen and the unit on the bench is not one of these six, what else we rebuild for Volkswagen is set out on the make page.

Sending a Bosch MA1.3 in for repair

These are repaired, not exchanged. The fault is found on the board and corrected at component level, so what goes back on the car is the unit that came off it, with its coding untouched.

The order of work does not vary. The unit is logged on arrival and inspected, electrical testing establishes where the fault actually sits, the failed components are replaced on the board under a microscope with temperature-controlled rework equipment, and the unit goes back on test before it is signed off. Every part of that happens in our own UK workshop, on our own equipment, by engineers we employ — none of it is subcontracted and none of it leaves the country.

You are told what has failed and what putting it right will cost before any chargeable work starts, and the repair carries a 24-month warranty. Price is on application.

Engine ECUs are the whole of what we do — the full scope of our engine ECU repair covers petrol, diesel, hybrid and direct-injection units across European, Japanese, Korean and American makes — and it works by post, from anywhere in the UK.

Send both Bosch references, the Volkswagen Group number and the engine when you get in touch. If your reference is not on this page, our engineers will confirm coverage for that specific unit rather than guess at it — tell us what the label says on the Repair Form.

The references this designation covers are listed below.

Common part numbers associated with this type of unit