2007 Mercedes-Benz S550

The 2007 Mercedes-Benz S550 is a luxury sedan known for its comfort, technology, and powerful V8 engine. This model year offers a blend of sophistication and performance. The S550 is powered by a 5.5-liter V8 engine producing 382 horsepower and 391 lb-ft of torque, paired with a 7-speed automatic transmission. While praised for its smooth ride and opulent interior, some common complaints include electronic malfunctions and costly repairs. Potential buyers should be aware of potential issues with the air suspension, electrical systems, and engine components.

Engine

5.5L V8 Engine (M273)

• Balance Shaft Sprocket Wear
  • Description/Symptoms: A common issue with the M273 engine is premature wear of the balance shaft sprocket. Symptoms include a check engine light with codes related to camshaft timing, rough idling, and potential engine misfires. A chirping or rattling noise may also be audible from the engine bay.
  • Solution: Replacement of the balance shaft sprocket. This often involves removing the engine or performing extensive disassembly.
  • Estimated Cost to Fix: $2,500 - $5,000+
  • Recalls: None Found
• Intake Manifold Flap Motor Failure
  • Description/Symptoms: The plastic intake manifold can develop cracks or the flap motor can fail. Symptoms include a check engine light, reduced engine performance, poor fuel economy, and possible misfires. Diagnostic trouble codes (DTCs) often point to the intake manifold flap motor or related sensors.
  • Solution: Replacement of the intake manifold assembly, including the flap motor.
  • Estimated Cost to Fix: $800 - $1,500+
  • Recalls: None Found
• Camshaft Adjuster (Magnet) Issues
  • Description/Symptoms: Oil can leak through the camshaft adjuster magnets into the engine wiring harness. Symptoms can include oil contamination in the harness, check engine light, and potential misfires or performance issues.
  • Solution: Replacement of the camshaft adjuster magnets and cleaning or replacement of the affected wiring harness sections.
  • Estimated Cost to Fix: $500 - $1,500+ depending on the extent of the wiring harness damage.
  • Recalls: None Found

Transmission

7-Speed Automatic (722.9)

• Conductor Plate Failure
  • Description/Symptoms: The 722.9 transmission is known for conductor plate failure. Symptoms include erratic shifting, limp mode, failure to shift, and diagnostic trouble codes related to the transmission’s electronic control unit (TCU) or speed sensors.
  • Solution: Replacement of the conductor plate within the transmission. This requires dropping the transmission pan and valve body.
  • Estimated Cost to Fix: $800 - $1,800+
  • Recalls: None Found
• Valve Body Issues
  • Description/Symptoms: The valve body can experience wear and sticking valves, leading to harsh shifting, slipping, and delayed engagement of gears.
  • Solution: Valve body rebuild or replacement.
  • Estimated Cost to Fix: $1,000 - $2,500+
  • Recalls: None Found

Suspension

• Airmatic Suspension Failure
  • Description/Symptoms: The Airmatic air suspension system is prone to leaks and compressor failures. Symptoms include the car sitting low on one or more corners, the suspension not leveling properly, error messages on the dashboard, and the air compressor running excessively or not at all.
  • Solution: Replacement of leaking air struts (shocks), the air compressor, or the air distribution valve block. Identifying the specific component that is failing is crucial.
  • Estimated Cost to Fix: $1,000 - $2,500+ per strut, $500 - $1,200+ for the compressor, $300 - $800+ for the valve block.
  • Recalls: None Found

Electrical

• EIS (Electronic Ignition Switch) Failure
  • Description/Symptoms: The EIS, also known as the keyless go module, can fail, leading to the inability to start the car, key recognition issues, and a generally unresponsive ignition system.
  • Solution: Replacement of the EIS module and potentially reprogramming or re-keying the system.
  • Estimated Cost to Fix: $800 - $2,000+
  • Recalls: None Found
• SAM (Signal Acquisition Module) Issues
  • Description/Symptoms: The SAM modules control various electrical functions. Failure can cause issues with lighting, wipers, door locks, and other electrical components.
  • Solution: Replacement or reprogramming of the faulty SAM module.
  • Estimated Cost to Fix: $500 - $1,500+ depending on the module and labor.
  • Recalls: None Found

Exterior

• Sunroof Issues
  • Description/Symptoms: The sunroof mechanism can fail, causing the sunroof to become stuck, make excessive noise, or leak.
  • Solution: Repair or replacement of the sunroof motor, tracks, or seals.
  • Estimated Cost to Fix: $300 - $1,200+
  • Recalls: None Found

Interior

• Command System Malfunctions
  • Description/Symptoms: The COMAND system, which controls navigation, audio, and other functions, can experience glitches, freezing, or complete failure. This may include display issues, inability to control features, or system reboots.
  • Solution: Software updates, repair, or replacement of the COMAND unit.
  • Estimated Cost to Fix: $300-$2,000+ depending on severity.
  • Recalls: None Found

Summary

The 2007 Mercedes-Benz S550 offers a luxurious driving experience but is prone to several common issues. The most significant concerns revolve around the engine (balance shaft, intake manifold), transmission (conductor plate, valve body), Airmatic suspension, and electrical systems. Repairs can be costly, especially those related to the engine and suspension. Potential buyers should have a pre-purchase inspection performed by a qualified mechanic specializing in Mercedes-Benz vehicles to identify any existing or potential problems. The severity of these issues can range from minor inconveniences to major mechanical failures, making thorough maintenance records and a careful inspection essential before purchase.