I had Service Suspension light come on. Everything works, aero, normal off road 1+2 so the dealer checked the code and said the Rrear sensor was not working. I cleaned the ground to the frame, (corroded) but light still on. Can you replace the sensor without loosing the air in the system? Is the dealer the only option to purchase the sensor? I do all the maintenance on my 2019 so can anyone describe the steps or have a link to a video?