My 2003 E500 says “stop, car too low” on the dash. Any time that I leave my car sitting overnight the car will lower itself almost completely to the ground, except for the drivers front. The air pump works and I can’t find any leaks. Most times, I can get the car to raise back up within a few minutes. Sometimes though I can’t get it to raise up at all. This is the same in warm and cold weather. Occasionally it will flash a visit workshop message, but it will just go away and not come back up. I’ve also left the battery unhooked for a few hours to try to reset the computer. What could be wrong?