Identifying your ECU (Bosch MED17.3.x and friends)

Pick your model, year, and engine in the order intake — for catalogued cars it preselects the ECU family we expect. That expectation comes from a per-car library, not guesswork.

Alfa Romeo petrols of the MultiAir era commonly carry Bosch MED17.3.x ECUs (MED17.3.0, MED17.3.1, MED17.3.3 depending on car and year); earlier and diesel cars carry other Bosch families. The intake flow shows the current supported list — it, not this guide, is the authority.

When your read tool connects, it identifies the ECU before doing anything — typically showing the family, the hardware number, and the software/calibration number.

That report is the cleanest confirmation there is: it reflects what is actually in your car right now. Note the numbers; they help the tuner cross-check your intake answers against the uploaded file.

The ECU itself carries a printed label with the Bosch part number and often the family marking (for example "MED17.3.3"). On many Alfa models the ECU sits in the engine bay near the battery or bulkhead.

Only check the label if it is visible without dismantling anything. Unbolting covers or connectors to read a sticker is not worth it when the tool report and intake flow already agree.

Do not unplug the ECU connectors to get a better look at the label. Disconnecting control units can log faults and upset learned settings — and the label adds nothing the tool report has not already told you.

If the tool reports a different family than the intake flow expected — a swapped ECU, an unusual market variant, a mid-year change — pick the "Other / not listed" path in the intake instead of forcing the closest option.

That routes your order to manual human assessment rather than an automatic analysis built on the wrong assumption. Slower, but correct.