RoadVitals

2021 BMW M340I Problems

Owner-reported complaints filed with NHTSA, grouped by component

Data refreshed

Owner complaintsComplaints are reports submitted to NHTSA by owners and drivers. NHTSA does not verify most reports before publishing them, and a complaint does not establish that a defect exists. Volume is influenced by how many of a vehicle were sold, how long it has been on the road, and how much attention an issue has received.
11
Latest Jul 2, 2026
Components namedHow many of our component categories appear on at least one report for this model year. One report can name several.
8
Crash or fire reportedComplaints whose submitter recorded that a crash or a fire occurred. These are the reporter's own answers on the NHTSA form, not verified findings.
0

What this page shows

Everything below is an owner-reported complaint submitted to NHTSA about the 2021 BMW M340I, grouped by the component NHTSA recorded on the report. These are not confirmed defects, and they are not recalls. NHTSA does not verify most reports before publishing them, and a category with more reports in it is not evidence that a part is defective.

Complaints are reports submitted by owners and drivers to NHTSA. They are not verified and do not establish that a defect exists.

Reports by component

Ranked by how many owner reports name each component category

  • Engine743.8%
  • Electrical212.5%
  • Powertrain (other)212.5%
  • Suspension16.3%
  • Brakes16.3%
  • Transmission16.3%
  • Fuel system16.3%
  • Steering16.3%

Percentages are of component mentions. A single complaint can name more than one component, so these do not sum to the total complaint count.

Each component in detail

What the reports in each category say, in the owners' own words

Engine

Reports naming the engine itself — including stalling, misfires, oil consumption, cooling and internal engine components.

7
reports

From owner reports, verbatim

I have been smelling a burning odor in the vehicle for almost a year which the dealership and an independent shop had not been able to diagnose. The car was recently throwing Drivetrain Error codes which prompted a visit to the dealership. They found that the 48v battery and negative cable are burnt and quoted $5680 to replace the battery and cables. After investigating I found that there were recalls for this issue on other BMWs, including the same year and model of my vehicle, but my VIN is not pulling up a recall. The issue is a fire risk and a very expensive repair that should be covered by the manufacturer due to a known defect.

NHTSA ID 11747887 · filed Jul 2, 2026

The BMW B58TU oil pump thermoplastic component issue that can cause catastrophic failure to the engine. The the gen 1 oil pump was made from plastic and after issues were discovered, they switched to metal oil pumps. However this known issue is something that BMW has not addressed in the models 2019-2021 that came with the inferior oil pump.

NHTSA ID 11747283 · filed Jun 29, 2026

Too few reports in this category for a page of its own — they appear in the full complaint list.

Electrical

Reports naming the electrical system — wiring, battery, charging, control modules, infotainment and electrical accessories.

2
reports

From owner reports, verbatim

I have been smelling a burning odor in the vehicle for almost a year which the dealership and an independent shop had not been able to diagnose. The car was recently throwing Drivetrain Error codes which prompted a visit to the dealership. They found that the 48v battery and negative cable are burnt and quoted $5680 to replace the battery and cables. After investigating I found that there were recalls for this issue on other BMWs, including the same year and model of my vehicle, but my VIN is not pulling up a recall. The issue is a fire risk and a very expensive repair that should be covered by the manufacturer due to a known defect.

NHTSA ID 11747887 · filed Jul 2, 2026

Here’s a strong version that sounds frustrated but still credible and harder to dismiss: I’ve owned many vehicles over the years, and this BMW has been, without question, the most problematic car I’ve ever had. The list of issues has been absurd for a vehicle in this price range and from a brand that markets itself as a premium luxury manufacturer. The sunroof failed, I’ve had multiple tire blowouts under normal driving conditions, the drive bar/suspension was bent from what should have been a routine road bump, the engine oil housing/component failed, and now I’m dealing with coolant system and drivetrain problems as well. At this point, it feels like one major issue after another. I expected quality, reliability, and engineering excellence from BMW, but my experience has been the complete opposite. Instead, ownership has been stressful, expensive, and incredibly disappointing. A luxury vehicle should not have this many significant failures in such a short span of ownership. Between the repair costs, downtime, and constant concern over what will fail next, this car has completely destroyed my confidence in the BMW brand. I am documenting these issues formally because this ownership experience has been unacceptable.

NHTSA ID 11738468 · filed May 18, 2026

Too few reports in this category for a page of its own — they appear in the full complaint list.

Powertrain (other)

Powertrain reports that are not specifically the engine or transmission — driveshafts, axles, transfer cases and differentials.

2
reports

From owner reports, verbatim

Here’s a strong version that sounds frustrated but still credible and harder to dismiss: I’ve owned many vehicles over the years, and this BMW has been, without question, the most problematic car I’ve ever had. The list of issues has been absurd for a vehicle in this price range and from a brand that markets itself as a premium luxury manufacturer. The sunroof failed, I’ve had multiple tire blowouts under normal driving conditions, the drive bar/suspension was bent from what should have been a routine road bump, the engine oil housing/component failed, and now I’m dealing with coolant system and drivetrain problems as well. At this point, it feels like one major issue after another. I expected quality, reliability, and engineering excellence from BMW, but my experience has been the complete opposite. Instead, ownership has been stressful, expensive, and incredibly disappointing. A luxury vehicle should not have this many significant failures in such a short span of ownership. Between the repair costs, downtime, and constant concern over what will fail next, this car has completely destroyed my confidence in the BMW brand. I am documenting these issues formally because this ownership experience has been unacceptable.

NHTSA ID 11738468 · filed May 18, 2026

While driving through an intersection and making a left turn, a failure of the engine water pump pulley caused the pulley to break apart. This led to damage to the coolant line and tensioner, sudden coolant loss, and the serpentine belt slipping off. The failure occurred mid-turn, causing the vehicle to skid and momentarily lose steering control. I narrowly avoided a collision with an oncoming vehicle that was stopped at a red light. The vehicle was towed to an independent repair shop, where mechanics confirmed that the water pump pulley had failed and caused the resulting damage. The vehicle is just over 4 years old and has approximately 58,000 miles. This type of failure—especially in a well-maintained vehicle with all scheduled maintenance completed on time—is unexpected and presents a serious safety concern.

NHTSA ID 11656393 · filed Apr 23, 2025

Too few reports in this category for a page of its own — they appear in the full complaint list.

Suspension

Reports naming suspension components — springs, struts, shocks, control arms and related hardware.

1
report

From owner reports, verbatim

Started as low creaking noise coming from front left wheel. Slow speeds, over small bumps. Over time (one month), creaking noises became louder and more frequent. At that time, steering was starting to feel stiff when turning to the left. Taken to 2 BMW dealerships who said it was just a noise and that both tie rods would have to be replaced. Upon further investigation, these noises and handling are a result of the torque being too tight at the factory upon manufacturer.

NHTSA ID 11692586 · filed Oct 10, 2025

Too few reports in this category for a page of its own — they appear in the full complaint list.

Brakes

Reports naming service brakes, the antilock braking system, brake hoses, master cylinders or the parking brake.

1
report

From owner reports, verbatim

The contact owns a 2021 BMW M340I. The contact stated while driving various speeds, the vehicle independently shifted from reverse(R) to drive(D) to park(P). The contact stated that while driving approximately 10 MPH and attempting to stop the vehicle, the brake pedal was depressed and went to the floorboard. The contact stated that the brake failed to operate as designed. The vehicle was towed to a dealer who diagnosed that the vacuum pump needed to be replaced. The vehicle was repaired. The contact stated that an unknown transmission repair was performed. The manufacturer was made aware of the failure. The approximate failure mileage was 4,000.

NHTSA ID 11491782 · filed Nov 1, 2022

Too few reports in this category for a page of its own — they appear in the full complaint list.

Transmission

Reports naming the automatic or manual transmission, including shifting behaviour, shudder, slipping and transmission control modules.

1
report

From owner reports, verbatim

The contact owns a 2021 BMW M340I. The contact stated while driving various speeds, the vehicle independently shifted from reverse(R) to drive(D) to park(P). The contact stated that while driving approximately 10 MPH and attempting to stop the vehicle, the brake pedal was depressed and went to the floorboard. The contact stated that the brake failed to operate as designed. The vehicle was towed to a dealer who diagnosed that the vacuum pump needed to be replaced. The vehicle was repaired. The contact stated that an unknown transmission repair was performed. The manufacturer was made aware of the failure. The approximate failure mileage was 4,000.

NHTSA ID 11491782 · filed Nov 1, 2022

Too few reports in this category for a page of its own — they appear in the full complaint list.

Fuel system

Reports naming fuel storage or delivery — tanks, pumps, lines, injectors and fuel leaks.

1
report

From owner reports, verbatim

Here’s a strong version that sounds frustrated but still credible and harder to dismiss: I’ve owned many vehicles over the years, and this BMW has been, without question, the most problematic car I’ve ever had. The list of issues has been absurd for a vehicle in this price range and from a brand that markets itself as a premium luxury manufacturer. The sunroof failed, I’ve had multiple tire blowouts under normal driving conditions, the drive bar/suspension was bent from what should have been a routine road bump, the engine oil housing/component failed, and now I’m dealing with coolant system and drivetrain problems as well. At this point, it feels like one major issue after another. I expected quality, reliability, and engineering excellence from BMW, but my experience has been the complete opposite. Instead, ownership has been stressful, expensive, and incredibly disappointing. A luxury vehicle should not have this many significant failures in such a short span of ownership. Between the repair costs, downtime, and constant concern over what will fail next, this car has completely destroyed my confidence in the BMW brand. I am documenting these issues formally because this ownership experience has been unacceptable.

NHTSA ID 11738468 · filed May 18, 2026

Too few reports in this category for a page of its own — they appear in the full complaint list.

Steering

Reports naming the steering system — racks, columns, power-steering assist and steering linkage.

1
report

From owner reports, verbatim

Started as low creaking noise coming from front left wheel. Slow speeds, over small bumps. Over time (one month), creaking noises became louder and more frequent. At that time, steering was starting to feel stiff when turning to the left. Taken to 2 BMW dealerships who said it was just a noise and that both tie rods would have to be replaced. Upon further investigation, these noises and handling are a result of the torque being too tight at the factory upon manufacturer.

NHTSA ID 11692586 · filed Oct 10, 2025

Too few reports in this category for a page of its own — they appear in the full complaint list.

Higher-selling and older vehicles accumulate more reports. Counts are not failure rates and are not directly comparable between vehicles that sold in very different numbers.

Elsewhere on this vehicle

Data sources

Data on this page last refreshed .