The ESP and BAS warning lights may illuminate due to a failed brake light switch. Replacement of the failed switch should correct this concern.Google+
Car Problem Reports
Mercedes-Benz CLS550 Brake Light Switch Failure May Cause ESP/BAS Warning Lights
Mercedes-Benz CLS550 Problem
Average Mileage: 40,500 mi (36,000 mi - 45,000 mi)
ESP warning light comes on from time to time.
Visitor, 2008 Mercedes-Benz CLS550, 45,000 mi
! ESP Inoperatible comes on time to time over past 5 days? Taking to dealer to take care of.