BMW quietly changed the ECU in the M2, M3 and M4 for the 2026 model year. The S58 cars built from July 2026 (M3 G80 and G81, M4 G82 and G83) and from August 2026 (M2 G87) meet Euro 7 and carry a new Bosch ECS1049 ECU in place of the MG1CS049 the earlier cars used. New ECU, new protection, and for a few weeks nobody could touch them.
On 4 September Autotuner released bench read and write for the ECS1049. The ECU is read in under three minutes and written in thirty seconds, and it does not need to be opened. So the very latest M cars can be tuned in the same visit as the 2021 to 2025 cars, and the file is developed the same way, on our own rolling road in Maidstone.
What the S58 gives
The S58 is one of the most rewarding engines we tune. The M3 and M4 Competition leave the factory at 510 PS and 650 Nm; a Stage 1 on the standard hardware takes that to around 600 PS and 750 Nm, and with downpipes a Stage 2 goes further. The M2 G87 starts at 480 PS and responds the same way. The gearbox, the ZF 8HP, gets its own file so the shifts and torque limits match the engine.
For owners
If you have a 2026 M2, M3 or M4, book it in as normal. Put the registration into the tuning builder for the figures and price, or read the M3 G80 case study to see the before and after curves from the dyno.
For dealers
ECS1049 files are available through the file service the same as any other BMW. If you are tuning M cars regularly, the Autotuner is the tool that reads this ECU today.
