Some specific diagnostic software is able to remove speed limit: for volvo with VCADS, for MB with DAS, for Scania with SDP3, for DAF with DAVIE etc. Here is an detail instruction on changing Vmax or top speed for Mercedes Benz AMG models with MB SD Connect C4 star diagnostic system.
Mercedes Benz WIFI MB SD Connect C4 STAR OBD2 Diagnostic tool
MB STAR DAS/XENTRY software HDD (need to activate EOL function)
Dell D630 laptop running Win XP home
Remove Benz AMG model’s speed limit with DAS/XENTRY:
MB SD Connect Compact 4 multiplexer software is well installed and activated on Dell D630 laptop before the package send out
Connect the SD Connect C4 diagnostic system with vehicle via USB or WIFI wireless connection
Open and run XENTRY software on the desktop
Select vehicle series: SL230
Select specific vehicle model
The STAR XENTRY will display full vehicle information, select an application on the left-hand side to perform diagnosis or search for document for the selected vehicle.
Follow and accept the system prompt, come to “Main groups” screen, select “Control units”, press F3
Select “Drive” control module, press F3
Select last option: “ME-SFI 2.8-Motor electronics 2.8”, press F3
First of all select “Fault codes” to clear all stored DTCs, then select “Event memory” to make sure there is no memory exists
Select “Development data” option
Select “Control unit adaptations”, press F3
Select “Control unit adaptations (Variant coding)”, press F3
Find out “Fahrzeug-Code. Vmax” option form the drop-down list. Select the top speed value you want to change form the list, like 250km/h, press F3 to save settings
The top speed value has been changed.
Back to main program and exit the MB STAR XENTRY/DAS diagnostic software.