2006 Mercedes-Benz SL600

The 2006 Mercedes-Benz SL600 is a luxurious and powerful roadster featuring a twin-turbocharged 5.5L V12 engine producing 493 horsepower and 590 lb-ft of torque. Other engine options available in the SL lineup for 2006 included a 3.5L V6 (SL350-European market only), a 5.0L V8 (SL500), and a 5.4L Supercharged V8 (SL55 AMG). A 7-speed automatic transmission (7G-Tronic) was paired with some models. Owners often praise the SL600 for its comfortable ride, powerful engine, and retractable hardtop. Common complaints include the high cost of maintenance and repairs, as well as the complexity of the electrical system.

Engine

5.5L Twin-Turbo V12 (M275)

• Oil Leaks
  • Description/Symptoms: Oil leaks can develop from various locations, including the valve cover gaskets, oil cooler lines, and front crankshaft seal. Visible oil drips under the car, oil consumption, and the smell of burning oil are common symptoms.
  • Solution: Replacing the leaking gaskets or seals is the typical repair.
  • Estimated Cost to Fix: $200 - $1,500+ depending on the location of the leak and labor.
  • Recalls: None Found
• Ignition Coil Failure
  • Description/Symptoms: Misfires, rough idling, and a noticeable decrease in power. The check engine light will usually illuminate.
  • Solution: Replacement of the faulty ignition coil(s). It’s often recommended to replace coils in pairs or all at once.
  • Estimated Cost to Fix: $150 - $400+ per coil, including labor.
  • Recalls: None Found
• ABC (Active Body Control) Pump Failure
  • Description/Symptoms: The ABC system relies on a hydraulic pump driven by the engine. If the pump fails, the suspension will lose its ability to adjust, resulting in a very rough ride and a warning message on the instrument cluster.
  • Solution: Replacement of the ABC pump.
  • Estimated Cost to Fix: $1,000 - $2,500+, including labor and fluid flush.
  • Recalls: None Found

Transmission

5-Speed Automatic (722.6)

• Transmission Conductor Plate Failure
  • Description/Symptoms: Erratic shifting, limp mode, and failure to shift into certain gears. The check engine light will often illuminate.
  • Solution: Replacement of the transmission conductor plate.
  • Estimated Cost to Fix: $800 - $1,500+, including labor, fluid, and filter.
  • Recalls: None Found
• Slipping or Harsh Shifting
  • Description/Symptoms: The transmission slips between gears or shifts harshly. This can be caused by low fluid, worn clutches, or valve body issues.
  • Solution: A transmission service (fluid and filter change) might resolve minor issues. More severe cases may require valve body repair or a transmission rebuild.
  • Estimated Cost to Fix: $300 (for fluid/filter) to $3,000+ (for rebuild).
  • Recalls: None Found

Suspension

• Active Body Control (ABC) System Leaks and Failures
  • Description/Symptoms: The ABC system, designed for superior handling and ride comfort, is prone to leaks in the hydraulic lines, struts, and valve blocks. Symptoms include the car sitting low, uneven ride height, warning lights, and fluid leaks.
  • Solution: Repair or replacement of leaking components, flushing the system, and sometimes replacing the ABC pump.
  • Estimated Cost to Fix: $500 - $3,000+ depending on the component. Strut replacement can be particularly expensive.
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: The EIS can fail, preventing the key from being recognized and the car from starting.
  • Solution: Replacement of the EIS and reprogramming.
  • Estimated Cost to Fix: $800 - $1,800+, including labor and programming.
  • Recalls: None Found
• SAM (Signal Acquisition Module) Failure
  • Description/Symptoms: The SAM controls various electrical functions. A faulty SAM can cause issues with lights, wipers, windows, and other electrical components.
  • Solution: Replacement of the faulty SAM and reprogramming.
  • Estimated Cost to Fix: $500 - $1,500+, including labor and programming.
  • Recalls: None Found
• Battery Drain
  • Description/Symptoms: The battery drains quickly, especially when the car is not driven frequently. This can be due to a faulty component not shutting down properly.
  • Solution: Diagnosis to find the source of the drain and repair or replace the faulty component.
  • Estimated Cost to Fix: $100 - $500+ depending on the issue.
  • Recalls: None Found

Exterior

• Retractable Hardtop Malfunctions
  • Description/Symptoms: The retractable hardtop can experience issues with its operation, including getting stuck, failing to open or close, or making unusual noises.
  • Solution: Diagnosing the specific issue (hydraulic pump, sensors, latches) and repairing or replacing the faulty component.
  • Estimated Cost to Fix: $500 - $3,000+ depending on the complexity of the repair. Hydraulic pump replacement is a common and expensive repair.
  • Recalls: None Found

Interior

• Seat Control Module Failure
  • Description/Symptoms: The power seats may stop working or move erratically.
  • Solution: Replacement of the seat control module.
  • Estimated Cost to Fix: $300 - $1000+, including labor and programming.
  • Recalls: None Found
• Center Console Control Knob Failure
  • Description/Symptoms: The central control knob used to access various multimedia features may become unresponsive or malfunction.
  • Solution: Replacement of the control knob assembly.
  • Estimated Cost to Fix: $200-$800+, including labor.
  • Recalls: None Found

Summary

The 2006 Mercedes-Benz SL600 offers exhilarating performance and luxurious features but is prone to several potentially costly issues. The ABC suspension system, electrical components, and retractable hardtop are particularly susceptible to problems. While some repairs are relatively minor, others can be very expensive due to the complexity of the vehicle and the cost of specialized parts. Potential buyers should carefully inspect the car’s service history and consider a pre-purchase inspection by a qualified Mercedes-Benz mechanic.