VW / Audi / Seat / Skoda (VAG) Bosch M3.8.5 Engine ECU Repairs

Type: Bosch Engine Management
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT187195

Note: This ECU may also fit other models.

Read the vehicle-manufacturer reference in the first row of the table at the foot of this page and it stops almost as soon as it starts: 06A 906 018, with nothing after it. That is the complete reference for that unit. Every other reference on this page begins with those same characters and then adds a letter or two.

So on the M3.8.5, 06A 906 018 is doing two jobs at once. On one car it is a whole part number. On the others it is only the opening of a different one. Anyone who reads the number off the label, gets as far as 018 and stops has copied the part these units all share and left behind the part that tells them apart.

Why knowing the car does not narrow the reference

Those trailing letters are not a trim code or a market code. Across the nine references listed below, published records name four marques against that one base number: Audi, Seat, Skoda and Volkswagen.

That is the difficulty for anyone working back from the car. Knowing the unit came out of a Volkswagen rules out very little here, and knowing it came out of an Audi or a Seat rules out no more. Every application we can trace in those records is a 1.8 as well, so engine size does not separate them either.

The badge and the capacity are the first two things most people reach for, and on this designation neither gets close to a single reference. What identifies the unit is the one or two characters at the end.

What the Volkswagen and Skoda records name

0261204438 is the bare one, the row with no letters after 06A 906 018. Three separate records place it on a Volkswagen Golf IV, the Mk4, with the 1.8 petrol engine: a UK trade listing, a European parts entry filed against the Golf IV (1J1) 1.8, and a catalogue record headed for a Golf 1.8 and typed as an M3.8.5.

06A 906 018 CL, Bosch 0261206076, is a Golf too. A UK listing, a European parts record and a third entry against the same Bosch number all give a Golf Mk4 1.8.

06A 906 018 DJ, Bosch 0261206144, is the one reference here that reaches two marques by itself. Separate records name it against a Skoda Octavia 1.8 and against a Volkswagen Golf IV 1.8.

0261204683 sits on the larger bodies. A UK listing gives it against a Volkswagen Sharan, and further records name the Sharan and the Seat Alhambra together, 1.8 in each case.

The M3.8.5 is not the only Bosch designation we keep a part-number table for on Volkswagen cars; the Volkswagen engine ECU designations we cover are gathered in one place.

What the Audi and Seat records name

Three of the nine references are documented against the same car. 06A 906 018 AK (Bosch 0261204675), 06A 906 018 CD (Bosch 0261204993) and 06A 906 018 CN (Bosch 0261206078) are each named against an Audi A3 1.8, by UK and European listings alike.

That is the marque problem one level down, and it is worth pausing on. Establishing that a unit came out of an A3 does not get you to a reference either. It takes nine down to three, and the last two characters still have to do the rest.

The Seat entries run the same way. 0261204878 is named against a Seat Toledo by two UK listings and a European stock record, one of which pairs it with the Leon. 06A 906 018 GC, Bosch 0261206587, is named against the Leon and the Toledo together by European records, and against a Toledo by a UK listing.

Seat accounts for three of the model lines documented on this page: the Leon, the Toledo and the Alhambra. The Seat cars whose engine ECUs we repair are grouped separately.

What a repair on one of these boards involves

Every unit is logged in, inspected and put on the bench before anyone forms a view about it. The board is tested electrically, the fault is traced to the components responsible for it, and the work is done at that level: the failed parts are renewed under a microscope with temperature-controlled rework equipment, and the board that arrived is the board that goes back.

That work is carried out by our own engineers, in our own UK workshop, on our own test equipment. Nothing is subcontracted and nothing is sent abroad. We do not start chargeable work until we have told you what the testing found and you have agreed to it, and when the repair is finished the unit goes back through testing before it leaves. It carries a twenty-four month warranty on the repair itself.

Reading the number off the label

When you write the reference down, write all of it. The letters after 06A 906 018 are the part that gets left off. They are small, they sit at the end, and they read like an afterthought. On this designation they are the number.

Copy the ten-digit Bosch reference from the case as well. It is printed separately from the vehicle-manufacturer number and it is the second thing we check, so a photograph of the label is usually quicker than typing either of them out.

Then tell us what the unit came out of. The car will not identify the reference on its own, which is the point of the four marques above, but it is a useful cross-check and it shows up straight away when the number read off the label does not match the vehicle it was taken from.

Sending an M3.8.5 in

We work by post, and units reach us from every part of the UK. There is no counter to bring one to, and nothing in the service depends on how far away you are. Pack the unit so that it cannot move inside the box.

Put the reference, the Bosch number and the car into our Repair Form, and our engineers will confirm the unit is one we cover and come back to you with what the testing found.

The nine references below are the ones this designation is recorded against on our own tables, each with the vehicle-manufacturer number that goes with it.

Common part numbers associated with this type of unit