2010 Mercedes S-Class Owner's Manual - Page 492

490 What to do if ... Brake Problem ! The yellow ABS indicator lamp comes on while the engine is running. Possible causes/consequences and M Solutions The brake system is still functioning normally but due to a malfunction, the ABS, the BAS, the BAS PLUS, the ESC, the hill-start assist system, the HOLD function, the Adaptive Brake Lights, the PRE-SAFE® system, and the PRE-SAFE® Brake are unavailable. The ATTENTION ASSIST is disabled. X Continue driving with added caution. Wheels may lock during hard braking, reducing steering capability. X Adjust driving to be consistent with reduced braking responsiveness. X Read and observe messages that may appear in the multifunction display (Y page 452). X Have the system checked at an authorized Mercedes-Benz Center as soon as possible. Failure to follow these instructions increases the risk of an accident. The brake system still functions normally but due to insufficient power supply, the ABS, the BAS, the BAS PLUS, the ESC, the hill-start assist system, the HOLD function, the Adaptive Brake Lights, the PRE-SAFE® system, and the PRE-SAFE® Brake are unavailable. The ATTENTION ASSIST is disabled. When the voltage is above the required value again, the ABS is operational again. The ABS indicator lamp should go out. X Continue driving with added caution. Wheels may lock during hard braking, reducing steering capability. X Adjust driving to be consistent with reduced braking responsiveness. X Read and observe messages that may appear in the multifunction display (Y page 452). X If the ABS indicator lamp does not go out: Have the alternator and the battery checked. Practical hints ! The yellow ABS indicator lamp comes on while the engine is running.