G20 / G21 — 3 Series (2019–2025)
The G20 (sedan) and G21 (Touring) 3 Series is one of the most popular platforms for coding due to its wide availability and large community.
Quick Facts
- Production: 2019–2025
- Head unit: MGU (ID6/ID7), ID8 on LCI (2023+)
- OBD port: Standard location, driver's side footwell
- Recommended tool: BimmerCode (easy) or E-Sys (full access)
Popular Coding Changes
Exterior
| Mod | Module | Tool | Difficulty |
|---|
| Ambient Lighting customization | BDC | BimmerCode / E-Sys | Easy |
| Cornering lights always on | BDC | E-Sys | Medium |
| Fold mirrors on lock | BDC | BimmerCode | Easy |
| Needle sweep on start | KOMBI | BimmerCode | Easy |
| Daytime running light brightness | BDC | E-Sys | Medium |
Interior / Display
Comfort / Functional
| Mod | Module | Tool | Difficulty |
|---|
| Start-stop memory | DME | BimmerCode | Easy |
| Exhaust burble / pops | DME | E-Sys | Medium |
| Seatbelt chime delay | BDC | E-Sys | Medium |
| Lock confirmation horn | BDC | BimmerCode | Easy |
| Auto hold default on | DME / EMF | BimmerCode | Easy |
G20 LCI Notes (2023+)
The LCI (Life Cycle Impulse / facelift) models switched to iDrive 8 with the curved display. Some key differences:
- The head unit module changes from
HU_MGU to HU_MGU2
- Some BimmerCode features may not be available yet on the LCI
- E-Sys requires updated PSdZData files for LCI modules
- Some FDL coding paths have changed compared to pre-LCI
Tips
- The G20 shares many modules with the G22 (4 Series Coupé) and G26 (4 Series Gran Coupé) — most coding changes apply across all three
- M340i and 330i share the same BDC and HU modules; only DME differs
- Always note your I-level before coding (visible in E-Sys or BimmerCode)