Reliable Auto DB

2021 BMW M340i reliability

Is it reliable?

Owners have filed 11 complaints with NHTSA about the 2021 BMW M340i over 6 years — 1 per year. That is more complaints per year than most M340i years here — over the median of the other years, which is 0. NHTSA has 6 recalls on file, including Seat belts, Seats, and Buckle.

2020 BMW M340i
Photo by Harvey Bold, resized from the original. Wikimedia Commons CC0
Complaints

11

Per year

1

Recalls

6

Years on the road

6

What owners report

The complaints owners file most often name Engine (7 of 11), then Powertrain (3) and Electrical system (2). The most filings arrived in 2026 (6 of 11).

Next to 2020 and 2022

The 2020 M340i has 53 complaints, 1 per year, and the 2022 has 7 complaints, 1 per year. The 2021 has fewer complaints per year than the 2020. The 2021 has more complaints per year than the 2022.

The complaint rate is complaints filed in this year’s first 3 years on the road, divided by however many of those years have passed. Recalls are a separate count. The numbers are for the US-market 2021 BMW M340i. How we count. Data as of .

Recalls (6)

Recall Seat belts 2023-08-16 · NHTSA campaign 23V584000
Summary 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."
Remedy 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 Seats 2023-03-29 · NHTSA campaign 23V211000
Summary 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.
Remedy 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.
Recall Seat belts 2021-07-21 · NHTSA campaign 21V554000
Summary 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."
Remedy 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).
Recall seat belts, front, buckle 2021-04-28 · NHTSA campaign 21V298000
Summary 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.
Remedy 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.
Recall back-over prevention, sensing system, camera 2021-02-19 · NHTSA campaign 21V096000
Summary 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."
Remedy 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.
Recall electrical system, 12V/24V/48V battery 2020-12-09 · NHTSA campaign 20V761000
Summary 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.
Remedy 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.

Complaints by component (11 total)

Engine
7
Powertrain
3
Electrical system
2
Fuel and propulsion system
1
Service brakes
1
Steering
1
Suspension
1
Crash-flagged

0

Fire-flagged

0

Injury reports

0

Death reports

0

Complaints filed per year

12022220232202562026
Excerpts from recent NHTSA complaint filings
  • "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…"
    Electrical system, Engine · filed 2026-07-02
  • "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.…"
    Engine · filed 2026-06-29
  • "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…"
    Engine · filed 2026-05-28
  • "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…"
    Powertrain, Electrical system, Fuel and propulsion system · filed 2026-05-18
  • "I am reporting a safety concern with BMW vehicles equipped with the B58 Technical Update (B58TU) engine, primarily in 2019–2021 model years. These vehicles use a variable-displacement oil pump containing an internal…"
    Engine · filed 2026-05-15

Fuel economy

Trim Engine Transmission Drive City Hwy Combined Annual fuel cost
M340i 3L, 6-cyl Automatic (8-speed) Rear-wheel drive 23 32 26 MPG $3050
M340i xDrive 3L, 6-cyl Automatic (8-speed) All-wheel drive 22 31 25 MPG $3200

Specs and fitment

G20 generation, 2020–present
Body styles Sedan
Oil SAE 0W-20 (B58; confirm BMW LL spec on under-hood label)
Tire size 225/35R19, 225/40R18, 225/45R17, 255/30R19, 255/35R18 (trim-dependent; staggered) front / 255/30R19, 255/35R18 (trim-dependent; staggered) rear

Known issues for this generation

Recall 21V598000 covers certain 2020 M340i and M340i xDrive models (with 540i, X3 M40i, X4 M40i, 745Le, and other B58 applications) for an engine concern on that campaign list; dealers perform the remedy described in NHTSA's campaign text. Recall 20V355000 covers certain 2019-2020 M340i and M340i xDrive models (with Z4, X3M, X4M, and 330i xDrive) for a tie rod assembly that may fail. Recall 19V755000 covers certain 2020 M340i models (with 330i) where the interior trunk release cable may have been incorrectly routed.

Compare

Previous year 2020 BMW M340i Next year 2022 BMW M340i See every BMW M340i model year →

Frequently asked questions

Is the 2021 BMW M340i reliable?

Owners have filed 11 complaints with NHTSA about the 2021 BMW M340i over 6 years — 1 per year. That is more complaints per year than most M340i years here — over the median of the other years, which is 0. NHTSA has 6 recalls on file, including Seat belts, Seats, and Buckle.

What are common problems with a 2021 BMW M340i?

The complaints owners file most often name Engine (7 of 11), then Powertrain (3) and Electrical system (2). The most filings arrived in 2026 (6 of 11).

Is the 2021 BMW M340i more reliable than the years next to it?

The 2020 M340i has 53 complaints, 1 per year, and the 2022 has 7 complaints, 1 per year. The 2021 has fewer complaints per year than the 2020. The 2021 has more complaints per year than the 2022.

Has the 2021 BMW M340i been recalled?

The 2021 BMW M340i has 6 recalls on file with NHTSA. See the recalls table on this page for dates, components, and remedies.

How many complaints have owners filed about the 2021 BMW M340i?

Owners have filed 11 complaints about the 2021 BMW M340i with NHTSA.

What mpg does a 2021 BMW M340i get?

EPA-rated combined fuel economy for the 2021 BMW M340i is 25.5 MPG. See the fuel economy table on this page for city and highway figures by engine and transmission.

What engine oil does a US BMW M340i use?

SAE 0W-20 (B58; confirm BMW LL spec on under-hood label)

What tire sizes fit a US BMW M340i?

Published US specs commonly list front 225/35R19, 225/40R18, 225/45R17, 255/30R19, 255/35R18 (trim-dependent; staggered) and rear 255/30R19, 255/35R18 (trim-dependent; staggered); confirm on the door jamb placard for your trim.

What NHTSA recalls affect the US BMW M340i?

Recall 21V598000 covers certain 2020 M340i and M340i xDrive models (with 540i, X3 M40i, X4 M40i, 745Le, and other B58 applications) for an engine concern on that campaign list; dealers perform the remedy described in NHTSA's campaign text. Recall 20V355000 covers certain 2019-2020 M340i and M340i xDrive models (with Z4, X3M, X4M, and 330i xDrive) for a tie rod assembly that may fail. Recall 19V755000 covers certain 2020 M340i models (with 330i) where the interior trunk release cable may have been incorrectly routed.