Depollution System Faulty and Radiator fan

Happy Ramadan everyone, good forum. Brothers, as you know, my vehicle is 1.6 thp 308 manual 2008 model. My car gives a Depollution system fault and runs the radiator fan constantly, as soon as I start it, the fan starts directly. It continues for 3-5 minutes after stopping. There is no fall in traction, there is no problem in walking. Turns on the engine warning light. Why does it happen, what should I do, my brothers, can you help me?

Happy ramadan.

Thank you brother, I left the tool to the master, I will write the developments

Happy Ramadan to everyone again, due to insurance, my car made a mistake and automatically took it into self-protection, so it started. A few fuses were changed, cables were arranged, no problem, brothers, I paid 450 liras in total. (They write a lot about labor in TRNC, brothers)