2003 Mercedes S-Class Owner's Manual - Page 293

Practical hints What to do if ...? Problem Possible cause (USA only) (Canada only) The red brake warning lamp lights up while driving and you hear a warning sound. The red brake warning lamp lights up while driving. You are driving with the parking brake set. Release the parking brake ( page 44). Risk of accident! Carefully stop the vehicle and notify an authorized Mercedes-Benz Center. Do not add brake fluid! This will not solve the problem. Suggested solution ; 3 There is insufficient brake fluid in the reservoir. Warning! G Driving with the brake warning lamp illuminated can result in an accident. Have your brake system checked immediately if the brake warning lamp stays on. Don't add brake fluid before checking the brake system. Overfilling the brake fluid reservoir can result in spilling brake fluid on hot engine parts and the brake fluid catching fire. You can be seriously burned. ! If you find that the brake fluid in the brake fluid reservoir has fallen to the minimum mark or below, have the brake system checked for brake pad thickness and leaks. 293