Chip-Tools

ITDEENBGES

Mercedes FBS4 TCU replacement: available functions, software version alignment (.cff) and configuration backup

The TCU section of the FBS4 Manager allows a complete gearbox control unit swap: only the immo data (FBS data) is transferred, keeping the donor's calibrations, and the donor's software versions are aligned to those of the original gearbox.

Procedure

1. Check the unit is among those supported: VGS4-NAG2 7G-Tronic, VGS-NAG3 9G-Tronic, VGS-FDCT/VGS2-FDCT, VGS3-FDCT, 8-DCT, GT-DCT. Remember that VGS4NAG2 and DSM require the ABProg programmer.
2. If you are only replacing the TCU electronics, before removing anything save the original unit's configuration backup from "Utilities" > "Save all Config data".
3. Open the FBS4 Manager, select the TCU section and use "Info" to identify the unit; with "Save" you read and save the original TCU's FBS data.
4. On the donor module use the dedicated button to bring it to virgin state, then "Personalize" to write the saved FBS data (or the without-existing-data procedure, according to the chapter for that gearbox type).
5. Use the "VIN" button to write the vehicle's VIN to the donor TCU.
6. After personalization, align the software versions: press "Program" to bring the donor TCU's software versions up to those of the original gearbox.
7. In "Program" you have two options: load your own .cff files by browsing the PC, if you have them, or use the Abrites server to program the TCU with the correct software versions.
8. If you replaced the whole gearbox assembly, do not restore the original's configuration: keep the one already on the donor TCU.

Reference screenshots