It sounds like you've found it. It's located between the airbox and the fuel injection system.
Unplugging it won't work. The FI requires input from the MAS, and you won't have any success with that.
Also, from a warranty standpoint, it's probably covered, and if you monkey with it, they might deny you coverage under the emissons warranty. MB is not known for their tolerance of DIY attempts to fix warranty items.
1998 C230 "Black Betty"