I got this message (service 4 wheel steer) when I started my truck on the way home. all three indiators (2,4, and trailer pic) lit up together. When I got home I turned the truck off and back on and the message did not come back on. I did not know at that time but, the manual shows I should have turned it off and on before driving. Could this be a serious problem or just a reminder to change the quadsteer fluid? 2003 GMC Sierra Xtd cab Quadsteer 4x4. 123,031 miles on it.