Would help if I knew what car this is, but stabbing around at various C230 203 chassis coupes I found one with a C1110 fault code (third attempt first two C230s didn't have such a code). C1110 is stated to be a L6/2 (right front speed sensor) Line monitoring fault. Testing is speed signal while turning right front wheel and verifying input voltage above 11v.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician