Configuration du calculateur erronée après remplacement

A replacement module fitted without being told what vehicle it is in.

Modern modules are not built per vehicle; they are built per family and configured afterwards. One part number serves many variants, and the configuration is what tells it which engine, which gearbox, which options, which market and which equipment actually exist. Fitting one and leaving that at a default produces a module that works perfectly and is describing a different car.

That is why the symptom is so confusing: nothing is broken, and nothing behaves correctly. The module reports equipment the vehicle does not have and fails to report equipment it does; other modules reject what it publishes; and features are absent or behave as they would on a different variant.

The failure it most reliably causes is being blamed on the part. A vehicle that runs worse after a module replacement reads as a faulty new module, and the second one behaves identically because it will not be configured either. The corpus records the same pattern for engine modules, injection pumps and injectors — this is the general form of it.

So the first question after any module work is not what broke, but what was configured — and it is worth asking specifically, because configuration is a separate step from installation and from programming, and it is the one most often skipped.

A second-hand module is the harder case. Many carry a vehicle identity that cannot simply be overwritten, and one locked to another vehicle may never function whatever is done to it — which is worth establishing before buying rather than after.