BMW 428i: DSC off, Sport+ stays

On our BMW 428i, Sport+ gave us the engine sound, throttle response and aggression we wanted for drifting. Holding the DSC button to turn traction control fully off brought back mild, Comfort-like engine behaviour.

For our drift use, that fallback was almost unusable. We wanted DSC fully off while keeping the engine calibration we had selected.

Keep Sport+ when DSC is off

Our modification is designed to retain the Sport+ engine calibration after the long press.

This work concerns the engine profile. Dashboard labels, gearbox settings and chassis modes are separate.

The idea in code

Illustrative pseudocode using invented names:

# Before: the unwanted fallback
selected_profile = "Sport+"
dsc_state = "OFF"
engine_calibration = "Comfort-like"

# Goal: keep the selected engine profile
if (selected_profile == "Sport+"
        and dsc_state == "OFF"):
    engine_calibration = "Sport+"

The actual implementation depends on the ECU software. These examples show the intended behaviour, without exposing the custom ROM details.

Tested on our 428i

Development car	Details
Vehicle	2015 BMW 428i, F32
Engine	N26
DME diagnostic profile	Bosch MEVD172P
ECU software (SWFL)	00001BC9-029.110.002
Calibration software tag	9VS9G01B