I recently bought a Mercedes s63 amg 2009. The suspension is all the way down, Fluid tank is full. Dash shows red abc warning, 0 pressure in abc sensor. I tried pulling the return line from radiator to abc reservoir, to see if it pump really isn’t pumping or is it just a bad sensor. Tried actuation test nothing comes out from the line. If anyone had similar problem please share your experience. And is replacing a pump will solve my problem or there’s something else that might cause it.