2020 Mercedes-Benz S450L

The 2020 Mercedes-Benz S450L is a luxury sedan known for its refined driving experience, opulent interior, and advanced technology. The S450L is powered by a 3.0-liter turbocharged inline-6 engine with EQ Boost, producing 362 horsepower and 369 lb-ft of torque. Other engine options for the 2020 S-Class include a 4.0-liter V8 biturbo and a 6.0-liter V12 biturbo, both with significantly higher power outputs. A common like about the S450L is its comfortable ride and plethora of luxury features. Some dislikes include the complex infotainment system and high repair costs. All engines are paired with a 9G-TRONIC 9-speed automatic transmission.

Engine

3.0L Turbocharged Inline-6 (M256)

• Failed ignition coils
  • Description/Symptoms: Engine misfires, rough idling, loss of power, check engine light.
  • Solution: Replace the faulty ignition coils.
  • Estimated Cost to Fix: $200 - $400+ per coil replaced (parts and labor).
  • Recalls: None Found
• Failed Auxiliary Coolant Pump
  • Description/Symptoms: Overheating, lack of cooling.
  • Solution: Replace the auxiliary coolant pump.
  • Estimated Cost to Fix: $300 - $500+ (parts and labor).
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic (725.0)

• Harsh Shifting/Hesitation
  • Description/Symptoms: Rough or jerky gear changes, hesitation when accelerating, especially at lower speeds.
  • Solution: Software update, valve body replacement or transmission replacement.
  • Estimated Cost to Fix: $150 (software update) - $3000+ (transmission replacement).
  • Recalls: None Found

Suspension

• Air Suspension Leaks
  • Description/Symptoms: Vehicle sitting unevenly, especially after being parked overnight, compressor running excessively or not at all, “Car too Low” warning message.
  • Solution: Locate and repair the air leak (often in the air springs or air lines), replace faulty air spring or compressor.
  • Estimated Cost to Fix: $800 - $2000+ per air spring replaced.
  • Recalls: None Found

Electrical

• Malfunctioning MBUX System
  • Description/Symptoms: Screen freezing, lagging, unresponsive touch controls, random reboots, navigation errors, inability to connect to Mercedes Me services.
  • Solution: Software update, replacement of the head unit in severe cases.
  • Estimated Cost to Fix: $0 (software update at dealership) - $1500+ (head unit replacement).
  • Recalls: None Found
• Battery Drain
  • Description/Symptoms: The car battery dies after short periods of inactivity, requiring frequent jump starts.
  • Solution: Diagnosing the parasitic drain (often caused by faulty modules or improperly shut-down systems), replacing the battery.
  • Estimated Cost to Fix: $200 - $500+ (diagnosis and repair) + $300+ (battery replacement).
  • Recalls: None Found

Exterior

• Panoramic Sunroof Issues
  • Description/Symptoms: Sunroof not opening or closing properly, unusual noises during operation, water leaks.
  • Solution: Repair or replace the sunroof motor, realign the sunroof, reseal the sunroof frame.
  • Estimated Cost to Fix: $300 - $1500+ depending on the issue.
  • Recalls: None Found

Interior

• Dashboard Creaking/Rattling
  • Description/Symptoms: Annoying creaking or rattling sounds emanating from the dashboard, particularly when driving over rough roads.
  • Solution: Identifying the source of the noise (often loose trim pieces or wiring harnesses) and securing them.
  • Estimated Cost to Fix: $100 - $500+ (depending on the complexity of the repair).
  • Recalls: None Found

Summary

The 2020 Mercedes-Benz S450L, while a luxurious vehicle, experiences some common issues. The most concerning relate to the air suspension and electrical systems due to their potential cost and impact on drivability. While some issues are minor and easily resolved, others, such as air suspension leaks or MBUX malfunctions, can be more expensive and require specialized repair. The severity of these issues ranges from simple inconveniences to potentially compromising the vehicle’s ride quality and functionality. Overall, pre-purchase inspections are recommended to identify potential problems, especially regarding the air suspension and electronics.