Exhaust gas temperature sensor

Gude people, I have a problem with my Kia Optima. The MKL lights up constantly and also let the error read out and also delete it again. The error was P247100 circuit exhaust gas temperature sensor series 1 probe 4 Vorrkat DPF signal too high. I now let the sensor change cost about 350€ with installation at Kia. Problem after 4 days went on again the MKL. What can this be a problem?