2024 Mercedes-Benz C300

The 2024 Mercedes-Benz C300 is a popular luxury sedan known for its sleek design, comfortable ride, and advanced technology. The standard engine is a 2.0L turbocharged inline-4 producing 255 horsepower and 295 lb-ft of torque, paired with a 9G-TRONIC 9-speed automatic transmission. While the C300 offers a refined driving experience, some owners have reported certain issues. Owners praise the luxurious interior and advanced technology features, while some criticize the high cost of maintenance and certain aspects of the infotainment system. This report focuses on issues beyond normal wear and tear that are frequently reported.

Engine

2.0L Turbocharged Inline-4 (M254)

• Engine Misfires
  • Description/Symptoms: Engine misfires, rough idling, check engine light illumination. Often caused by faulty ignition coils or spark plugs.
  • Solution: Replacement of the affected ignition coil(s) and/or spark plugs.
  • Estimated Cost to Fix: $200 - $500+
  • Recalls: None Found
• High-Pressure Fuel Pump Failure
  • Description/Symptoms: Difficulty starting, engine stalling, reduced engine performance, and potential fuel leaks.
  • Solution: Replacement of the high-pressure fuel pump.
  • Estimated Cost to Fix: $800 - $1500+
  • Recalls: None Found

Transmission

9G-TRONIC 9-Speed Automatic (725)

• Rough or Delayed Shifting
  • Description/Symptoms: Harsh or delayed shifts between gears, particularly during cold starts or under heavy acceleration. May also cause a clunking noise.
  • Solution: In some cases, a software update to the transmission control module (TCM) can resolve the issue. In more severe cases, valve body replacement or transmission replacement may be required.
  • Estimated Cost to Fix: $150 - $300+ for software update, $1500 - $4000+ for valve body replacement, $5000 - $8000+ for transmission replacement.
  • Recalls: None Found
• Transmission Slipping
  • Description/Symptoms: The engine revs up without a corresponding increase in vehicle speed. This can occur during acceleration or while maintaining a constant speed.
  • Solution: A transmission flush and fluid replacement may help in some cases. More severe cases may require replacement of the torque converter or a full transmission rebuild/replacement.
  • Estimated Cost to Fix: $300 - $600+ for fluid flush, $1500 - $3000+ for torque converter replacement, $5000 - $8000+ for transmission replacement.
  • Recalls: None Found

Suspension

• Air Suspension Leaks (if equipped)
  • Description/Symptoms: The vehicle sits unevenly, especially overnight. The air compressor may run frequently or continuously. Ride quality may be poor.
  • Solution: Replacement of the leaking air strut(s) or air lines.
  • Estimated Cost to Fix: $1000 - $2500+ per strut.
  • Recalls: None Found
• Premature Bushing Wear
  • Description/Symptoms: Clunking or squeaking noises from the suspension, especially when going over bumps. Handling may feel loose or imprecise.
  • Solution: Replacement of worn bushings (e.g., control arm bushings, sway bar bushings).
  • Estimated Cost to Fix: $300 - $1000+
  • Recalls: None Found

Electrical

• Infotainment System Freezing/Crashing
  • Description/Symptoms: The MBUX infotainment system freezes, crashes, or becomes unresponsive. This can affect navigation, audio, and other functions.
  • Solution: A software update may resolve the issue. In some cases, the infotainment unit may need to be replaced.
  • Estimated Cost to Fix: $0 - $300+ for software update, $1000 - $3000+ for unit replacement.
  • Recalls: None Found
• Sensor Malfunctions (Parking Sensors, Blind Spot Monitoring)
  • Description/Symptoms: Parking sensors give false readings or fail to detect objects. Blind spot monitoring system may not function correctly.
  • Solution: Diagnosis of the faulty sensor(s) and replacement.
  • Estimated Cost to Fix: $200 - $800+ per sensor.
  • Recalls: None Found

Exterior

• LED Headlight Failure
  • Description/Symptoms: One or more LEDs in the headlight assembly fail, resulting in reduced visibility.
  • Solution: Replacement of the entire headlight assembly.
  • Estimated Cost to Fix: $1500 - $3000+ per headlight.
  • Recalls: None Found

Interior

• Sunroof Issues
  • Description/Symptoms: Sunroof will not open/close, is slow to open/close, makes loud noises when operating, or leaks water.
  • Solution: Depending on the issue, solutions range from lubricating the tracks, to replacing the motor or the entire sunroof assembly.
  • Estimated Cost to Fix: $100 - $200+ for lubrication, $500 - $1500+ for motor replacement, $2000 - $4000+ for assembly replacement.
  • Recalls: None Found
• Seat Motor Malfunction
  • Description/Symptoms: The power seats may not adjust properly, or at all, due to a faulty motor.
  • Solution: Replacement of the affected seat motor.
  • Estimated Cost to Fix: $300 - $800+ per motor.
  • Recalls: None Found

Summary

The 2024 Mercedes-Benz C300, while a desirable luxury sedan, has some common issues that owners should be aware of. Engine misfires and high-pressure fuel pump failures can affect engine performance and reliability. Transmission issues such as rough shifting and slipping can also be costly to repair. Electrical problems, particularly with the infotainment system, can be frustrating. Suspension issues, and interior/exterior issues, such as the sunroof, can add to the overall cost of ownership. The severity of these issues varies, and repairs can range from a few hundred dollars for minor fixes to several thousand dollars for major component replacements. Buyers should carefully inspect used models and be prepared for potential maintenance costs associated with these common problems.