The active body control system can leak fluid from numerous areas, including the tandem pump, hydraulic lines, struts, and/or seals. If it is not repaired, the vehicle ride height could drop too low and cause damage to the undercarriage.Google+
Car Problem Reports
Mercedes-Benz SL550 Active Body Control System Can Leak Hydraulic Fluid
Mercedes-Benz SL550 Problem
Average Mileage: 50,040 mi (23,000 mi - 85,000 mi)
Visitor, 2009 Mercedes-Benz SL550, 28,400 mi
ABC hose broke- $1600 to repair
Visitor, 2008 Mercedes-Benz SL550, 56,000 mi
ABC pump making noise and not covered under warranty. Cost to repair $4400. I'm trading the car in.
Visitor, 2007 Mercedes-Benz SL550, 52,000 mi
Leak and repair cost $2600
Visitor, 2009 Mercedes-Benz SL550, 66,500 mi
ABC Malfunction warning on. Fluid leak visible under vehicle. Steering is impossibly hard.
Visitor, 2007 Mercedes-Benz SL550, 85,000 mi
leak in pressure hose. Install new hose& fluid $700
Visitor, 2007 Mercedes-Benz SL550, 28,000 mi
Leaking fluid and car ABC maintenance went on to stop car and take to mbz repair.
Visitor, 2007 Mercedes-Benz SL550
I have a 2009 SL550 and have just taken it in for this same problem. Glad to have read this report. The Service Dept is keeping my car another day to make sure it has no other leaks.