2021 BMW M340i Problems

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Complaints Reported

Complaints by Component

ENGINE

3 complaints

I am reporting a safety concern involving BMW vehicles equipped with the B58 Technical Update (B58TU) engine, commonly found in model years 2019–2021. These vehicles utilize a variable-displacement engine oil pump containing an internal thermoplastic adjusting component responsible for regulating oil pressure. Field failures are increasingly being reported in which this internal component fractures, resulting in sudden loss or instability of engine oil pressure. The failure frequently occurs during cold-start operation in low ambient temperatures. When the component fails, oil pressure regulation becomes erratic or is lost entirely. In many cases, drivers receive little or no actionable warning prior to engine damage or vehicle disablement. Reported precursor symptoms include inability to electronically measure engine oil level, abnormal oil pressure behavior, or sudden drivetrain malfunction warnings. Failures may rapidly progress to engine shutdown or severe mechanical damage caused by oil starvation. Loss of lubrication can cause the vehicle to become disabled without warning while driving or shortly after startup. This creates a safety hazard, particularly when vehicles become immobilized in active traffic or during winter conditions the cold is when they fail the most, where occupants may be exposed to freezing temperatures while awaiting assistance. As I waited for 4hr in -15c. Replacement of the oil pump requires extensive disassembly of the vehicle and repairs costed 8349 for just the pump, assuming the motor is unharmed. Owners are currently unable to determine whether their vehicles contain the original thermoplastic oil pump design or a later revised version utilizing metal internal components, as VIN-based parts information now identifies updated components in the car even when no replacement has occurred and the old components are actually in the car. Also, BMW has actively removed the plastic part number out of all dealer networks as well.

Mar 13, 2026

At approximately 20,000 miles, vehicle indicated excessively low oil. The dealer indicated oil level was excessively low but did not identify the problem,. The vehicle was filled and returned to owner. Within 1000 miles, the incident occurred again. Dealer replaced replaced the valve cover claiming that was the issue. Now within +/- 1000 miles, the oil level is again excessively low. I happen to have another identical BMW of the same year and same mileage having exactly the same problem (filing separate complaint).

Nov 03, 2023

STEERING,SUSPENSION

1 complaint

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.

Oct 10, 2025

POWER TRAIN

1 complaint

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.

Apr 23, 2025

POWER TRAIN,SERVICE BRAKES

1 complaint

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.

Nov 01, 2022

4.6/5.0

57 reviews

BMW M340i VIN Decoder — Free VIN Check Video Guide

Watch our quick BMW M340i VIN decoder walkthrough. Learn how to decode any BMW M340i VIN number to get full vehicle history, recall alerts, specifications, fuel economy (MPG), safety ratings, and known problems — completely free on ForCar.org.

Where to Find VIN for Problems Check

To check for problems and complaints on your 2021 BMW M340i, you'll need the VIN number. Find your VIN in one of these 4 common locations.

Where to Find VIN Number on 2021 BMW M340i for Problems Lookup - Dashboard, Door Jamb, Engine Bay, Documents

Understanding VIN Structure for Problem Reports

Each character in your 2021 BMW M340i 17-digit VIN helps identify specific complaints and problems affecting your vehicle model.

2021 BMW M340i VIN Structure for Complaint Verification - WMI, VDS, Check Digit, Model Year, Plant Code

How to Check 2021 BMW M340i Problems in 3 Steps

Locate Your VIN

Find the 17-character VIN on your 2021 BMW M340i dashboard (visible through windshield), door jamb, engine bay, or vehicle documents.

Review by Component

Browse owner-reported complaints organized by vehicle component (engine, transmission, brakes, electrical) to identify common issues and problem patterns for this model year.

Check Safety Issues

Review crash and fire incidents for each component to assess safety concerns. Contact your BMW dealer or report problems to NHTSA at SaferCar.gov.

Frequently Asked Questions

How many problems does the 2021 BMW M340i have?

The 2021 BMW M340i currently has 6 owner-reported complaints according to NHTSA database. These complaints are organized by component to help identify common issues.

What are the most common problems with 2021 BMW M340i?

The most common problems reported for the 2021 BMW M340i are organized by component above. Each component section shows owner-reported issues, crash reports, and fire incidents to help identify patterns and problem areas.

Where does this 2021 BMW M340i problem data come from?

All problem and complaint data for the 2021 BMW M340i comes directly from the National Highway Traffic Safety Administration (NHTSA) database. These are real complaints submitted by actual vehicle owners.

How do I report problems with my 2021 BMW M340i?

You can report safety problems with your 2021 BMW M340i directly to NHTSA at SaferCar.gov or call 1-888-327-4236. Your complaint helps identify patterns and may lead to recalls or investigations.

Where can I find my VIN to check problems?

Your 2021 BMW M340i VIN is located in 4 places: (1) Dashboard near windshield on driver's side, (2) Driver's door jamb sticker, (3) Engine bay, (4) Vehicle registration and insurance documents.

Is the 2021 BMW M340i reliable?

Reliability can be assessed by reviewing the number and severity of owner complaints for the 2021 BMW M340i. Check complaints by component, crash reports, and fire incidents above to evaluate potential issues and problem patterns.