2019 Mercedes-Benz S450L

The 2019 Mercedes-Benz S450L is a luxury sedan known for its smooth ride, opulent interior, and advanced technology. The S450L comes with a 3.0L turbocharged V6 engine producing 362 horsepower and 369 lb-ft of torque, paired with a 9G-TRONIC 9-speed automatic transmission. Other engine options include the S560 with a 4.0L V8, and AMG S63 with a more powerful version of the 4.0L V8. Owners generally appreciate the S450L’s comfort, quietness, and sophisticated features. However, some common complaints include the complexity of the infotainment system and occasional electronic glitches.

Electrical

• MBUX Infotainment System Freezing/Crashing
  • Description/Symptoms: The MBUX (Mercedes-Benz User Experience) system can freeze, become unresponsive, or spontaneously reboot. This can affect navigation, audio, climate control, and other vehicle functions integrated into the system.
  • Solution: Software updates from the dealer can often resolve these issues. In some cases, a hardware replacement of the MBUX module might be necessary.
  • Estimated Cost to Fix: Software updates may be covered under warranty. MBUX module replacement can range from $1,200 - $2,500+ depending on labor and parts.
  • Recalls: None Found
• Sensor Malfunctions (Parking Sensors, Blind Spot Monitoring, etc.)
  • Description/Symptoms: Various sensors around the vehicle can malfunction, leading to error messages, false alerts, or non-functionality of safety systems like parking assist, blind spot monitoring, lane keeping assist, and adaptive cruise control.
  • Solution: Diagnosis to determine the faulty sensor is required. Replacement of the affected sensor and recalibration of the system.
  • Estimated Cost to Fix: $300 - $1,000+ per sensor, depending on the sensor type and location.
  • Recalls: None Found
• Battery Drain Issues
  • Description/Symptoms: The car’s battery drains quickly, especially if the vehicle is not driven frequently. This can lead to difficulty starting the car or complete battery failure.
  • Solution: Investigate for parasitic drains caused by faulty modules or accessories. A software update may address certain issues. Battery replacement might be necessary, or an auxiliary battery may have issues.
  • Estimated Cost to Fix: $200 - $500+ for battery replacement; parasitic drain diagnosis can range from $150 - $500+ depending on complexity.
  • Recalls: None Found

Interior

• Sunroof/Moonroof Rattling or Failure
  • Description/Symptoms: Rattling noises from the sunroof/moonroof area, difficulty opening or closing the sunroof, or complete failure of the sunroof mechanism.
  • Solution: Inspection and lubrication of the sunroof tracks and mechanism. Repair or replacement of damaged components.
  • Estimated Cost to Fix: $150 - $800+ depending on the severity and parts needed.
  • Recalls: None Found
• Seat Adjustment Motor Failure
  • Description/Symptoms: One or more of the seat adjustment motors fails, preventing the seat from moving in a particular direction.
  • Solution: Replacement of the faulty seat adjustment motor.
  • Estimated Cost to Fix: $300 - $800+ per motor.
  • Recalls: None Found

Exterior

• No Issues Found

Engine

3.0L Turbocharged V6

• Oil Leaks
  • Description/Symptoms: Oil leaks can develop from various locations on the engine, such as valve cover gaskets, oil filter housing, or rear main seal. Visible oil spots under the car or a burning oil smell may indicate a leak.
  • Solution: Identification of the leak source and replacement of the affected gasket or seal.
  • Estimated Cost to Fix: $200 - $1,500+ depending on the location and complexity of the repair.
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic

• Rough Shifting/Hesitation
  • Description/Symptoms: The 9G-TRONIC transmission may exhibit rough or delayed shifting, especially when cold. Some owners report hesitation during acceleration or gear changes.
  • Solution: A transmission software update may address some shifting issues. In some cases, valve body replacement or transmission rebuild might be necessary.
  • Estimated Cost to Fix: Software update may be covered under warranty. Valve body replacement can range from $1,500 - $3,000+; transmission rebuild $3,000-$6,000.
  • Recalls: None Found

Suspension

• Air Suspension Leaks/Failure (If equipped)
  • Description/Symptoms: The Airmatic air suspension system (if equipped) can develop leaks in the air struts or air lines, leading to the vehicle sitting unevenly, a bumpy ride, or complete suspension failure. Error messages may appear on the dashboard.
  • Solution: Replacement of the leaking air strut or air line. Calibration of the air suspension system.
  • Estimated Cost to Fix: $1,000 - $3,000+ per strut, depending on location and parts.
  • Recalls: None Found

Summary

The 2019 Mercedes-Benz S450L, while luxurious, is prone to some electrical issues related to its complex infotainment system and sensors. Mechanical issues like oil leaks in the engine and rough shifting in the transmission are also reported. If the vehicle is equipped with air suspension, leaks and failures can be a concern. The severity of these issues ranges from minor software glitches to more expensive component replacements. Potential buyers should be aware of these common problems and factor in the potential cost of repairs when considering a used S450L.