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2020 BMW M340i

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By Research the Car 4 min read

The 2020 BMW M340i is a popular sport sedan praised for its performance, handling, and luxurious features. It’s equipped with a potent 3.0-liter turbocharged inline-six engine, producing 382 horsepower and 369 lb-ft of torque. The engine is paired with an 8-speed automatic transmission. While owners generally appreciate the M340i’s responsiveness, driving dynamics, and upscale interior, common complaints include certain electrical glitches, suspension noises, and some reported issues with the infotainment system. No other engine and transmission options are available.

Engine

3.0L Turbocharged Inline-Six (B58)

  • Rough Idle/Hesitation at Startup
    • Description/Symptoms: Some owners have reported a rough idle or hesitation upon starting the engine, especially in cold weather. This is sometimes accompanied by a check engine light.
    • Solution: This can be caused by faulty fuel injectors. Replacing the fuel injectors has resolved this issue in some cases.
    • Estimated Cost to Fix: $800 - $1500+ depending on the number of injectors replaced and labor costs.
    • Recalls: None Found
  • Coolant Leaks
    • Description/Symptoms: Coolant leaks from various points in the cooling system, including the water pump, thermostat housing, and radiator hoses. This leads to low coolant levels and potential overheating.
    • Solution: Identify the source of the leak and replace the affected component. This may involve replacing the water pump, thermostat, hoses, or even the radiator.
    • Estimated Cost to Fix: $300 - $1200+ depending on the specific component and labor costs.
    • Recalls: None Found

Transmission

8-Speed Automatic (ZF 8HP51)

  • Rough Shifting/Hesitation
    • Description/Symptoms: Some owners have reported instances of rough or delayed shifting, especially when the transmission is cold or under heavy load. This can manifest as a noticeable jerk or hesitation between gears.
    • Solution: In some cases, a software update can improve the transmission’s shifting behavior. In other cases, a transmission fluid flush and filter change may alleviate the issue. In severe cases, valve body replacement may be required.
    • Estimated Cost to Fix: Software update: $100 - $300. Fluid flush/filter change: $300 - $500. Valve body replacement: $1500 - $3000+.
    • Recalls: None Found

Suspension

  • Creaking/Squeaking Noises
    • Description/Symptoms: Some owners have reported creaking or squeaking noises emanating from the suspension, particularly when driving over bumps or uneven surfaces. This can be caused by worn or dry suspension bushings, ball joints, or sway bar links.
    • Solution: Inspect the suspension components for wear or damage. Replace any worn bushings, ball joints, or sway bar links. Lubricating the suspension components may temporarily alleviate the noise.
    • Estimated Cost to Fix: $200 - $800+ depending on the number of components replaced and labor costs.
    • Recalls: None Found
  • Adaptive Damper Malfunctions (if equipped)
    • Description/Symptoms: For vehicles equipped with adaptive dampers, some owners have reported malfunctions that result in a harsh or inconsistent ride quality. This may be accompanied by error messages on the dashboard.
    • Solution: Diagnose the cause of the malfunction using BMW diagnostic tools. This may involve replacing one or more of the adaptive dampers, control modules, or wiring harnesses.
    • Estimated Cost to Fix: $800 - $2000+ depending on the affected components and labor costs.
    • Recalls: None Found

Electrical

  • Infotainment System Glitches
    • Description/Symptoms: Some owners have experienced glitches with the iDrive infotainment system, including screen freezes, unresponsive touch controls, and connectivity issues with Apple CarPlay or Android Auto.
    • Solution: Try restarting the iDrive system. Check for software updates and install them. In some cases, a complete system reset may be necessary. If the problem persists, the iDrive control unit may need to be replaced.
    • Estimated Cost to Fix: Software update: Free (if available). System reset: Free. Control unit replacement: $800 - $2000+.
    • Recalls: None Found
  • Sensor Malfunctions (Parking Sensors, etc.)
    • Description/Symptoms: Malfunctions of various sensors, such as parking sensors, can occur. This results in false alerts or a complete failure of the sensor system.
    • Solution: Diagnose the affected sensor and replace it.
    • Estimated Cost to Fix: $200 - $500+ depending on the specific sensor and labor costs.
    • Recalls: None Found

Exterior

  • Automatic Trunk Malfunction
    • Description/Symptoms: The automatic trunk may have problems opening or closing, sometimes getting stuck or failing to operate correctly.
    • Solution: Check the trunk struts for damage. It is also possible the module needs to be replaced.
    • Estimated Cost to Fix: $200 - $500+ depending on the specific component and labor costs.
    • Recalls: None Found

Interior

  • Seat Motor Issues
    • Description/Symptoms: The power seat motor may fail or start making unusual noises.
    • Solution: Replacement of the seat motor may be needed.
    • Estimated Cost to Fix: $300 - $800+ depending on the specific motor and labor costs.
    • Recalls: None Found

Summary

The 2020 BMW M340i is generally a reliable vehicle. The severity and cost of these issues varies, with infotainment glitches and suspension noises being relatively minor annoyances, while engine issues like coolant leaks and transmission problems can be more expensive to address. While no recalls have been found, potential buyers should be aware of these common issues and inspect the vehicle thoroughly before purchasing.

BMW, M340i
BMW M340i 2020
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