Citroen C4 1.6 HDI

Hi everyone.
I bought a repossessed C4, and I was able to run a diagnostic. It's showing faults with the temperature sensor, cruise control, and something related to the key communication. Everything else seems to be working, but these three faults have occurred over 400 times between them, all intermittently, and I think they seem to be coming from the upper part of the dashboard or something like that. It's four years old, and I don't know if it's had its regular services; it currently has 34,000 km. Does anyone know anything about this?
Thanks in advance.