The Mercedes manual (CD) calls this part the "air flow sensor position indicator," or sometimes the "air flow sensor potentiometer" labeled "B2" in figure 07.3-013 entitled "Function Diagram of CIS-E Injection System." I don't see an air flow meter, per se, nor is it the throttle valve switch (S29/2) shown in that figure. Phil at the FastLane pointed me to something called an "EHA valve," but I am just not sure. Thanks, -rha