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Audi’s new generation of S and RS cars arrived with a new engine ECU. The 2025 S5 and the 2026 SQ5 run the 3.0 TFSI V6 on a Bosch MG1CS202; the 2026 RS5 runs its 2.9 TFSI on the MG1CS203. Both are Aurix TC389 units and, until July, neither could be read by any tool.
On 24 July Autotuner released bench read and write for both, after a one-off mail-in unlock. The ECU is read in two minutes and written in one, with checksums and a full backup handled by the tool. That puts the newest S5, SQ5 and RS5 on the same footing as the previous B9 cars we have been tuning for years.
Which cars
- Audi S5 (2025 on), 3.0 TFSI V6
- Audi SQ5 (2026 on), 3.0 TFSI V6
- Audi RS5 (2026 on), 2.9 TFSI V6
What it means
The 3.0 TFSI in the previous S5 and SQ5 responded well to a Stage 1: typically from 354 PS and 500 Nm to around 420 PS and 580 Nm on standard hardware. We expect the new car to behave the same way, and every figure we publish is measured on our own rolling road before the file goes out. The one-off unlock means the first visit needs the ECU out of the car for a few days; after that, it is a bench job in the workshop.
Owners: put your registration into the tuning builder for your car’s figures, or read the Audi S4 and S5 case study for the dyno curves. Dealers: MG1CS202 and MG1CS203 reads are handled through the file service as normal, and the Autotuner is the tool that reads them.
