How many NHTSA complaints have been filed about the 2021 Bmw M340i?

9 NHTSA complaints have been filed about the 2021 Bmw M340i between 2022-11-01 and 2026-05-28. Top reported components: ENGINE (5), POWER TRAIN (3), ELECTRICAL SYSTEM (1). Source: NHTSA Office of Defects Investigation.

2021 Bmw M340i Maintenance Schedule

Manufacturer-recommended service intervals for the Condition-Based Service and open recall alerts for your 2021 Bmw M340i.

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How BMW schedules service: Condition-Based Service

BMW vehicles use Condition-Based Service (CBS) — the dashboard shows each service item with its own remaining mileage and time, calculated by sensors. The schedule below shows BMW's underlying targets. BMW Ultimate Care covers the first 3 years / 36,000 miles of factory-scheduled maintenance on most new vehicles.

6 Open Recalls

Source: NHTSA

SEAT BELTS

Campaign #21V554000 · 21/07/2021

Issue: BMW of North America, LLC (BMW) is recalling certain 2021 2 Series (230i, 230i xDrive, M240i, M240i xDrive), 330e, 330e Xdrive, 4 Series Coupe (430i, 430i xDrive, M440i xDrive) M4 Coupe, M4 Competition Coupe, BMW 4 Series Convertible (430i, M440i), BMW X1 sDrive28i, xDrive28i, 2 Series Gran Coupe (228i, 228i xDrive, M235i xDrive), M2 Competition Coupe, 330i, 330i xDrive, M340i, M340i xDrive, M3, M3 Competition, 530i, 530i xDrive, 540i, 540i xDrive, MINI Hardtop 2 Door (Cooper, CooperS, JCW), X2 sDrive28i, X2 xDrive28i, X2 M35i, Z4 sDrive30i, Z4 M40i, MINI Hardtop 2 Door (Cooper SE), MINI Convertible (Cooper, Cooper S, JCW), MINI Clubman (Cooper S, Cooper S All4, JCW), MINI Countryman (Cooper, Cooper All4, Cooper S, Cooper S All4, JCW All4), Rolls Royce Ghost, MINI Countryman (Cooper S E All4), Rolls Royce Phantom, Rolls Royce Cullinan, and Toyota Supra vehicles. The passenger seat belt Automatic Locking Retractor (ALR) may deactivate early, before the webbing fully retracts. As such, these assemblies fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."

Risk: During a crash, a seat belt retractor that does not function as intended increases the risk of injury.

Fix: Dealers will inspect the seat belt retractors (including the seat belts) and, if necessary, replace the retractors, free of charge. Owner notification letters were mailed on September 3, 2021. Owners may contact BMW customer service at 1-800-525-7417; 1-866-825-1525 (MINI); 1-877-877-3735 (Rolls Royce); and 1-888-270-9371 (Toyota).

ELECTRICAL SYSTEM:12V/24V/48V BATTERY

Campaign #20V761000 · 09/12/2020

Issue: BMW of North America, LLC (BMW) is recalling certain 2021 M340i xDrive, M440i xDrive Coupe, 530i, 530i xDrive, 540i, 540i xDrive, 740Li, 740Li xDrive, 840i Gran Coupe, 840i xDrive Gran Coupe, X5 sDrive40i, X5 xDrive40i, X6 sDrive40i, X6 xDrive40i, and X7 xDrive40i vehicles. The connection between the 48-Volt battery and the starter-generator may not have been assembled properly, which can cause increased electrical resistance at the connections.

Risk: Increased electrical resistance can increase the risk of a fire.

Fix: BMW will notify owners, and dealers will inspect the connection between the 48-Volt battery and the starter-generator assembly, replacing it if necessary, free of charge. The recall is expected to begin April 12, 2021. Owners may contact BMW customer service at 1-800-525-7417.

BACK OVER PREVENTION: SENSING SYSTEM: CAMERA

Campaign #21V096000 · 19/02/2021

Issue: BMW of North America, LLC (BMW) is recalling certain 2019-2021 X3 sDrive30i, X3 xDrive30i, X3 M40i, X3M, X4 xDrive30i, X4 M40i, M550i, X4M, X5 sDrive40i, X5 xDrive40i, X5 xDrive50i, X5M, X5 M50i, X7 xDrive40i, X7 xDrive50i, X7 M50i, Alpina XB7, 330i, 330i xDrive, M340i, M340i xDrive, and 8 Series Coupe, Convertible and Grand Coupe, 840i, 840i xDrive, M850i xDrive, M8, 2020-2021 530e, 530e xDrive, 330e, 330e xDrive, 745Le, 745Le xDrive, X5 xDrive45e, X3 xDrive30e, X6 sDrive40i, X6 xDrive40i, X6 xDrive50i, X6 M50i, X6M, 530i, 530i xDrive, 540i, 540i xDrive, M550i xDrive, M5, 740i, 740Li, 740Li xDrive, M760i Drive, M760Li xDrive, 750Li xDrive Alpina, Alpina B7 xDrive, and 2021 4 Series Coupe 430i, 430i xDrive, M440i xDrive vehicles. When shifting into Reverse, a small portion of the rearview image may be obscured, or the screen may not illuminate. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 111, "Rear Visibility."

Risk: If the driver relies on only the rearview camera image, the missing or reduced rearview image view can increase the risk of a crash or injury.

Fix: BMW will notify owners, and dealers will inspect the rearview camera software and update it if necessary, free of charge. The recall began April 16, 2021. Owners may contact BMW customer service at 1-800-525-7417.

SEAT BELTS:FRONT:BUCKLE ASSEMBLY

Campaign #21V298000 · 28/04/2021

Issue: BMW of North America, LLC (BMW) is recalling certain 2021 330i, 330i xDrive, M340i, M3, and 330e xDrive vehicles. The bolt securing the seat belt assembly to the frame was not tightened to specification.

Risk: An improperly installed seat belt assembly may not restrain an occupant as expected, increasing the risk of injury.

Fix: BMW will notify owners, and dealers will inspect the front seat belt buckle assembly connection and, if necessary, replace it, free of charge. Owner notification letters were mailed on June 25, 2021. Owners may contact BMW customer service at 1-800-525-7417.

SEATS

Campaign #23V211000 · 29/03/2023

Issue: BMW of North America, LLC (BMW) is recalling certain 2019-2021 330i, 330i xDrive, M340i xDrive, 2020-2021 X3 sDrive30i, X3 xDrive30i, X3 M40i, X3M, 2021 X3 xDrive30e, X4 xDrive30i, and X4M vehicles. The seat frame may not have been welded properly to the seat rails.

Risk: An improperly welded seat frame may not properly restrain the occupant during a crash, increasing the risk of injury.

Fix: Dealers will replace the seat frame and back rest, free of charge. Owner notification letters were mailed May 22, 2023. Owners may contact BMW customer service at 1-800-525-7417.

SEAT BELTS

Campaign #23V584000 · 16/08/2023

Issue: BMW of North America, LLC (BMW) is recalling certain 2019-2022 330i, 330i xDrive, M340i, 2022 430i Coupe, 2021-2022 430i, M440i Convertible, and 2020-2022 228i xDrive Gran Coupe vehicles. The receiver audio module control unit software may fail to properly generate audible seat belt warnings to the driver to fasten their seat belt. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 208, "Occupant Crash Protection."

Risk: An audible chime that does not properly alert the driver to fasten their seat belt increases the risk of injury in a crash.

Fix: Dealers will update the receiver audio module software, free of charge. Owner notification letters were mailed October 12, 2023. Owners may contact BMW customer service at 1-800-525-7417.

Recall data refreshed Jun 7, 2026.

Essential maintenance

Critical for safety and preventing major damage

🛢️

Engine Oil Service (CBS)

Every 10,000 mi

Replace BMW Longlife-04 (LL-04) full-synthetic oil and filter every 10,000 miles or annually — whichever the CBS system signals first. M-series engines may require shorter intervals; check the vehicle-specific iDrive screen.

Estimated cost — typical U.S. ranges

Dealer

~$120–$160

Shop

~$85–$115

DIY

~$25–$55

Full synthetic costs more than conventional. 5-quart 0W-20 + filter is the typical bill.

🧪

Brake Fluid Service (CBS)

Every 24,000 mi

Replace DOT 4 LV brake fluid every 2 years regardless of mileage. CBS triggers based on time, not miles, due to moisture absorption.

Every 60,000 mi

BMW xDrive AWD: replace transfer case fluid every 60,000 miles. Skipping this causes the most common xDrive failure — actuator stuck in 100/0 split.

Estimated cost — typical U.S. ranges

Dealer

~$105–$140

Shop

~$75–$100

DIY

~$15–$40

AWD/4WD vehicles only. Easy drain-and-fill on most platforms.

Recommended maintenance

Extends the life of your vehicle and improves comfort

🌬️

Microfilter (Cabin Air Filter)

Every 30,000 mi

Replace the activated-carbon microfilter every 30,000 miles. Most BMWs have a single combined cabin/charcoal filter behind the engine bay firewall.

Estimated cost — typical U.S. ranges

Dealer

~$60–$95

Shop

~$45–$70

DIY

~$15–$40

Usually behind the glovebox. Shops charge labor for a 10-minute job — easy DIY win.

🌡️

Engine Coolant (G48 / HT-12)

On condition / lifetime

BMW labels coolant as lifetime fill on most modern vehicles. Independent BMW specialists recommend replacement every 4-5 years to prevent water-pump and thermostat housing degradation.

Estimated cost — typical U.S. ranges

Dealer

~$285–$330

Shop

~$200–$235

DIY

~$25–$60

Use the manufacturer-specified coolant — wrong color/chemistry can damage the cooling system.

Known issues for this vehicle

What drivers and federal regulators have officially reported about the 2021 Bmw M340i.

Reported to NHTSA

NHTSA has 9 complaints on file for the 2021 Bmw M340i (2022-11 → 2026-05). We haven't reviewed and grouped them yet for this specific YMM — for now, the full list lives on NHTSA.

Top reported components: ENGINE (5) · POWER TRAIN (3) · ELECTRICAL SYSTEM (1)

Read all complaints on NHTSA →

Note: NHTSA also opened 1 defect investigation on this vehicle that closed without action.

Issues on other model years

Source: NHTSA Office of Defects Investigation (ODI). Complaint data refreshed Jun 13, 2026. Investigation data refreshed Jun 13, 2026.

We display NHTSA's record with attribution; we don't editorialize on what these complaints mean for any specific vehicle.

Typical U.S. ranges. Actual quotes vary by shop, parts choice, and vehicle condition.

How we estimate: Dealer = OEM parts × 1.4 + labor × $165/hr. Shop = parts + labor × $115/hr. DIY = parts only.

This maintenance schedule for the 2021 Bmw M340i reflects BMW's published service intervals and the Condition-Based Service system. Your actual service needs may vary based on driving conditions, climate, and vehicle usage. Always consult your owner's manual for model-specific recommendations.

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