When the S mode is selected 2nd gear is used when moving off with low load with the lever in D or 3.When moving off with high load(heavy throttle) First gear is selected for maximum acceleration.It will also allow later upshifts of the transmission.
When the E mode is selected The car will start off in second gear whilst the selector is in D or 3 in all load conditions.There is no part throttl kickdown possible,although Full kickdown is still possible.The Box will shift up sooner at all load speeds.
When the E/S switch is operated it passes vacuum from the swichover valve on the bulkhead to the vacuum element on the kickdown cable.This operates a pin inside the lower part of the cable which pushes against a rod attached to the Bell crank of the control pressure valve inside the box.
This limits the travel of the control pressure valve and thus limits the control pressure,dependent upon throttle position.
When full kickdown is operated in E,the kickdown switch disconnects the power to the switch over valve and allows the vac element to disengage from The E mode whilst the kickdown switch is pressed.
The E/S mode switch has no effect,and never has had any effect.on the engine management system.
It does not alter fueling or timing.
The reason the throttle feels sharper is,there is no resistance from the bellcrank spring when in S,so the pedal will feels slightly lighter and you retain part throttle kickdown which will make the car feel sprightly.
Concerning the other gearpositions,if the 2 position is selected at standstill it will engage first gear in either E or S,it will hold this gear until the redline or you shift out of 2.If you shift out of 2 and then back into 2, it will then hold 2 gear until you shift into 3.This way you can theorectically drive the car as a semi auto.This is a debatable practice,but Mercedes have never confirmed(to my knowledge) whether it is a "feature" or unrecommended to do this.As such i dont recommend this practice(Although i use it this way myself with no damage,but it aint gonna cost me a new gearbox if it goes bellyup

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Basically thats how it works and what it does.
Edited by Ukmerctechie, Wed Dec 3, 2008 3:20 pm.