Gazhock

Hi. I bought a 2nd hand citroen yesterday and all seemed hunky dory. I drove it home and to and from work last night, on the motorway I tried the cruise control and it was great. This morning though, on the computer it says 'speed control faulty' or something along those lines. Anyone any idea. The car was also serviced last month (apparently, the stamp from the garage is there) but the service light came on and went off after about 10 seconds. Again, anyone any ideas??