VW / Audi / Seat / Skoda (VAG) Bosch MED 17.5.20 Engine ECU Repairs

Type: Bosch Engine Management
Fits: VAG – Audi / Seat / Skoda / Volkswagen (VW)
Fuel: Petrol
Ref: ECUT374295

Note: This ECU may also fit other models.

The engine is the one thing a Bosch MED17.5.20 does not leave open. The references that independent records tie to an engine all come back as a 1.4, and all but one are recorded specifically as a 1.4 TSI petrol. What the unit does not tell you on its own is the car it came from, and that is where this page spends its words.

That order of questions matters once the ECU is out of the car. Knowing the engine is a 1.4 TSI does not yet tell a garage which MED17.5.20 it is holding, and the references here are spread across Volkswagen, Audi and Seat models in a pattern that does not follow the badge as neatly as might be expected.

Why the 1.4 TSI is already a given

The standard applied throughout is simple. An engine, an engine code or a car is stated here only where at least two independent sources put it against that exact reference; anything resting on a single listing is left out, however plausible it looks.

On capacity, the records leave nothing to argue about. Wherever they give one for a reference in the table at the foot of this page, it is 1.4. The only reference not also recorded as a TSI is 0261 S06 105, printed with 03C 906 022 BK, where the records agree on the 1.4 and go no further. This page does not go further either.

The Audi reference, 0261 S04 394 with 03C 906 022 AN, is the one place where two engine names appear side by side. Two independent sources describe it as a 1.4 TSI and two as a 1.4 TFSI. A listing that uses either name is describing the same 1.4 on the same reference.

One engine code is named on this page: CAXA, which two independent sources record against 0261 201 788. Codes resting on a single listing are left out, and output figures are not given at all.

With the engine settled, what remains is the reference itself, and this is where the car starts to matter, though not quite in the way most people expect.

The cars behind the ten references

Volkswagen makes up most of the table. The Golf, the Eos and the Passat account for most of those references, each named by two or more independent sources against the reference it sits beside. Audi and Seat have one reference apiece: the A3 for Audi, and for Seat a single reference recorded on the Leon, the Altea and the Toledo.

Reference by reference, the Volkswagen side reads like this. 0261 201 928, printed with 03C 906 022 G, is recorded on the Passat. 0261 S04 039 (03C 906 022 H) and 0261 S04 397 (03C 906 022 AM) are both recorded on the Eos. 0261 S04 405 (03C 906 022 J) and 0261 201 788 are both Golf references, and 0261 S06 105 is recorded on the Jetta.

If the Volkswagen in front of you turns out to carry a different unit altogether, the wider run of Volkswagen engine ECUs we handle is the next place to look.

Why the model name does not lead to one reference

It is tempting to assume that one model means one reference. On this page it does not, and the badge alone will not find you a part number.

The Eos is the clearest case. It is recorded on two references here, 0261 S04 039 with 03C 906 022 H and 0261 S04 397 with 03C 906 022 AM, and each placement has its own independent sources: four for the first, seven for the second. Two Eos owners with the same 1.4 TSI can therefore be holding different MED17.5.20s.

The Golf gives the same answer. 0261 S04 405 and 0261 201 788 are both recorded on it, by six independent sources each, and both are recorded as a 1.4 TSI. Neither the model nor the engine separates those two; only the reference does.

The practical upshot is that the car confirms an identification but does not make one, and it is the label, not the logbook, that has to be read.

The Audi A3 and Seat references

The A3 reference is 0261 S04 394, printed with 03C 906 022 AN. Five independent sources pair those two numbers, and seven name the A3 as the car. If your Audi carries some other unit, the Audi applications beyond this A3 reference are listed separately.

The Seat reference is 0261 S04 396, printed with 03C 906 022 AQ. It is recorded on three Seat models, and the Leon is by some distance the most widely documented of them, with eight independent sources behind it; the Altea and the Toledo follow with three and two.

If a Leon, Altea or Toledo on your bench carries a different reference, look it up under Seat instead.

A unit from a Skoda, or from any car this page does not name, is not ruled out by any of this. Send the reference and we will confirm what it is; the top of the engine ECU repair tree shows the full range of what we take in.

Sending a MED17.5.20 in for repair

The service is mail-in and covers the whole of the UK. Each unit is logged on arrival, inspected and electrically tested before any repair is considered, so the fault is established on the bench rather than inferred from the symptoms the car was showing.

Repairs are carried out at component level. Our engineers trace the specific failure on the board and put that right, in our own UK workshop and on our own equipment, with nothing sent out to another firm. What goes back into the car is the unit that came out of it, repaired rather than swapped, and it is not released until it has passed final testing.

Once the diagnosis is complete, we tell you what has failed and what the repair involves, and no chargeable work starts until you have agreed to it. Every repair is covered by a 24-month warranty on the work carried out.

Three details from you make the identification straightforward: the ten-character Bosch number beginning 0261, the vehicle-manufacturer number beginning 03C with its trailing letters, and the car and engine the unit came from. Given what the records show about models and references, the first two carry more weight than the third. Fill in the Repair Form from the label, not from memory, and our engineers will confirm the unit before anything else happens.

The full list of ten references follows, Bosch number first.

Common part numbers associated with this type of unit