2010 Mercedes-Benz SL550

The 2010 Mercedes-Benz SL550 is a luxurious and sporty roadster, powered by a 5.5-liter V8 engine producing 382 horsepower and 391 lb-ft of torque. It came standard with a 7-speed automatic transmission. While owners often praise its elegant design, powerful engine, comfortable ride, and retractable hardtop, some common complaints include the high cost of maintenance and repairs, potential electrical issues, and the complexity of its numerous electronic systems. Other available engine options include the SL63 AMG and the SL65 AMG.

Engine

5.5L V8

• Valve Cover Gasket Leaks
  • Description/Symptoms: Oil leaks from the valve cover gaskets, often noticed as oil drips under the car or a burning smell.
  • Solution: Replace the valve cover gaskets.
  • Estimated Cost to Fix: $400 - $800+
  • Recalls: None Found
• Camshaft Adjuster Solenoid (Cam Magnet) Leaks
  • Description/Symptoms: Oil leaking from the camshaft adjuster solenoids (cam magnets). This can lead to oil entering the engine wiring harness and potentially damaging the engine control unit (ECU).
  • Solution: Replace the cam magnets with updated versions and clean the wiring harness.
  • Estimated Cost to Fix: $200 - $600+
  • Recalls: None Found
• Check Engine Light (Various Causes)
  • Description/Symptoms: Check engine light illumination. This can be due to a variety of issues, including oxygen sensor failure, catalytic converter problems, or issues with the fuel system. Diagnosis requires a scan tool to read the diagnostic trouble codes (DTCs).
  • Solution: Diagnose the underlying cause using a scan tool and repair or replace the faulty components.
  • Estimated Cost to Fix: Varies widely depending on the cause, from $100 to $2000+
  • Recalls: None Found

Transmission

7-Speed Automatic (7G-Tronic - 722.9)

• Conductor Plate Failure
  • Description/Symptoms: Erratic shifting, transmission slipping, getting stuck in gear, or a complete loss of drive. The transmission may go into “limp mode.” Diagnostic trouble codes (DTCs) related to the conductor plate will be stored.
  • Solution: Replace the conductor plate, which includes the transmission control unit (TCU). Often requires programming/coding to the vehicle.
  • Estimated Cost to Fix: $800 - $1500+
  • Recalls: None Found
• Torque Converter Issues
  • Description/Symptoms: Shuddering or vibrations at low speeds, particularly during acceleration. May also cause stalling.
  • Solution: Replace the torque converter.
  • Estimated Cost to Fix: $1500 - $3000+
  • Recalls: None Found

Suspension

• ABC (Active Body Control) System Leaks/Failures
  • Description/Symptoms: Vehicle leaning to one side, rough ride, ABC warning light illuminated, hissing noises from the suspension system. Leaks can occur from the pump, valve blocks, struts, or hoses.
  • Solution: Diagnose the source of the leak and replace the faulty component(s). This could involve replacing the ABC pump, valve blocks, struts, or hydraulic hoses. Sometimes a fluid flush and filter change can help.
  • Estimated Cost to Fix: $500 - $3000+ (depending on the component)
  • Recalls: None Found
• AirMatic Suspension Issues
  • Description/Symptoms: Suspension will not hold air pressure, ride height is off or inconsistent, error messages or malfunction indicators are present on the dash, and the vehicle’s suspension system may not operate normally.
  • Solution: Replace airmatic struts or air compressor to fix the issue.
  • Estimated Cost to Fix: $1000-$3000
  • Recalls: None Found

Electrical

• Battery Drain
  • Description/Symptoms: The car battery drains quickly, especially when the vehicle is not driven for a few days. This can be caused by a parasitic drain from a faulty module or electrical component.
  • Solution: Diagnose the source of the parasitic drain and repair or replace the faulty component. This often involves using a multimeter to measure current draw and isolating the circuit causing the drain.
  • Estimated Cost to Fix: $200 - $1000+ (depending on the source of the drain)
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: Various electrical issues, such as malfunctioning lights, wipers, or power windows. The SAM module controls many of the vehicle’s electrical functions, and its failure can cause a wide range of problems.
  • Solution: Replace the faulty SAM module and program it to the vehicle.
  • Estimated Cost to Fix: $500 - $1500+
  • Recalls: None Found
• Retractable Hardtop Malfunctions
  • Description/Symptoms: The retractable hardtop fails to open or close properly, or stops mid-cycle. This can be due to hydraulic issues, sensor problems, or a faulty control module.
  • Solution: Diagnose the cause of the malfunction and repair or replace the faulty components. This could involve hydraulic pump repair, sensor replacement, or control module replacement/reprogramming.
  • Estimated Cost to Fix: $500 - $3000+ (depending on the complexity)
  • Recalls: None Found

Exterior

• Convertible Top Hydraulic System Leaks
  • Description/Symptoms: Slow or non-functional convertible top operation, visible hydraulic fluid leaks near the pump, cylinders, or lines.
  • Solution: Identify the source of the leak and replace the faulty components (pump, cylinder, or lines).
  • Estimated Cost to Fix: $500 - $2500+ (depending on the component)
  • Recalls: None Found

Interior

• Center Console Control Knob Failure
  • Description/Symptoms: The COMAND system control knob becomes unresponsive or difficult to use.
  • Solution: Replace the control knob or the entire COMAND unit, if necessary.
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found
• Seat Heater Malfunctions
  • Description/Symptoms: The seat heaters fail to work or only work intermittently. This can be due to a faulty heating element or a problem with the control module.
  • Solution: Diagnose the cause of the malfunction and replace the faulty component.
  • Estimated Cost to Fix: $200 - $800+
  • Recalls: None Found

Summary:

The 2010 Mercedes-Benz SL550, while a luxurious and enjoyable vehicle, can present owners with some potentially costly repairs. The ABC suspension system and the 7G-Tronic transmission are common sources of problems, with repairs often exceeding $1000. Electrical issues can also be frustrating and expensive to diagnose and fix. Potential buyers should be aware of these potential issues and budget accordingly for maintenance and repairs. A pre-purchase inspection by a qualified Mercedes-Benz mechanic is highly recommended.