Velocimeter Ssang Yong, Korando

Good afternoon.
I have a ssangyong, Korando Diesel 2.0 model, year 2014 and a few days ago when going speed (between 30 and 80 km/hr approx) the speedometer began to oscillate, when the vehicle goes down the vehicle gives pulls, I took it to a scanner but nothing appears.
Does anyone have any idea that can help me?
Thank you so much