2009 Carrera 2S. When you drive it hard on cornering, the traction control activates on and off. When it activates, the car makes a grinding noise coming from the front and rear wheels. The noise is intermitent. When you are cornering and the grinding noise is being produced you turn traction control off(PSM) and the noise disappears. There is no difference with the suspension in sport on comfort mode. I just changed the 4 lower control arms. Original Porsche parts. This noise was not being made before.