The U11A600 code is often associated with issues such as:

Sometimes a simple "soft reset" by turning the car off and on can clear transient communication glitches.

You do not need a dealership-level scan tool, but you do need a professional-grade Mercedes scanner (like XENTRY, iCarsoft MB V2.0, Autel MaxiSys, or ThinkDiag). Generic OBD2 readers will show only P0106 (Manifold Absolute Pressure/Barometric Pressure Circuit Range/Performance).