How to open SECRET Mercedes-Benz hidden workshop menu on E-Class 

Easy step by step how to go onto your workshop menu. ignition on and release parking brake, gearbox on Neutral.
Make sure the car its on a flat level ground and use some wheel chocks.
Ignition on press home and back button for 3 seconds and after press ok button, this will take you to the workshop menu.
if you want to exit from this menu just lock and unlock the car with your remote!!!