Locked ECUs from 2020: What MG1 and MD1 Mean
Why newer vehicles can no longer be tuned through the OBD port — and what alternatives exist.
What has changed
MG1 and MD1 are engine ECU generations from Bosch that have been widely installed in the VW Group and other manufacturers since around 2018 — MG1 for petrol engines, MD1 for diesel.
The key difference compared to their predecessors: the memory contents are cryptographically signed. The ECU checks at startup whether the software carries a valid signature from the manufacturer. A modified file loaded via OBD is simply rejected.
What alternatives remain
| Method | Access | Effort | For whom |
|---|---|---|---|
| OBD | Through the diagnostic port | Low | Only older ECUs before MG1/MD1 |
| Bench | ECU removed, on the workbench | Medium | The standard approach for MG1/MD1 |
| Boot | Direct access to the processor | High | When bench doesn't work, housing must be opened |
In practice, this means: for a vehicle from around 2020 onwards, the engine ECU typically needs to be removed for a performance upgrade. That's why chip tuning on a newer vehicle costs more and takes longer than on a ten-year-old one.
How to tell what you have
- Build year before 2018 — OBD almost always possible
- Build year 2018 to 2020 — varies depending on engine and market
- Build year from 2020 — generally bench or boot
- The only way to know for sure is via the ECU part number
Beware of "OBD tuning for everything"
Providers who promise a performance upgrade via OBD in 20 minutes for current vehicles are either not bypassing the signature check at all — in which case nothing happens except an error log entry — or they're using methods that permanently flag the ECU as tampered with.
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