The 2021 BMW M340i has 11 NHTSA owner complaints and 6 recalls on file (U.S. federal records, as of August 2026). The most-reported system is engine at 6 complaints (~$3,100 to repair). Source: NHTSA Office of Defects Investigation.
Solid reliability overall. Common issues are concentrated in a few systems.
0
Critical
6
Severe
0
Moderate
Should you avoid this 2021 M340i?
Acceptable — with caveats
Worth owning if you verify the specific issues below before you buy.
Reliability score 7.6/10 — above the segment average
6 recall campaigns on file
Our read of the federal NHTSA complaint and recall record for this exact year and model —
not a substitute for a pre-purchase inspection. How we score.
Buying a used 2021 BMW M340i? Check these first
Here's what this model is known to do — so you can inspect for it, price it in, or
make the seller fix it before you sign.
What to inspect on this specific car
engine — 6 owner reports
· ~$3,100 to fix
powertrain — 3 owner reports
· tends to show around 4,000 mi · ~$2,500 to fix
Recalls to confirm are done
Run the VIN from the listing — 6 active recalls on this model. Recall repairs are always free.
Verdict for buyers: 7.6/10 model. The priciest documented failure is
engine (~$3,100) — get the
seller's service records for it or inspect closely. Otherwise an average-risk used buy at a fair price.
We tell you what this model is known for and what to inspect — a vehicle-history report
tells you what this exact car has been through. Smart buyers get both.
A noise, a warning light, a repair quote, "should I buy this?" — get an answer grounded in
this vehicle's actual NHTSA record, not generic advice.
Dash light, leak, worn part — snap it and we'll read it against this car's record.
Photo attached — type a question or just hit Ask.
Answers use this vehicle's NHTSA complaint & recall record — owner-reported and unverified, not a diagnosis. Verify anything safety-critical with a mechanic.
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What owners are saying
recent NHTSA-filed complaints · verbatim
2021 M340i· engine
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…
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 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…
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…
Had a problem with your 2021 BMW M340i?
File a complaint with NHTSA → It's free and official — owner filings are what build the federal safety record behind this page.
Estimate your repair exposure
Drag to your current mileage. Numbers are derived from this vehicle's complaint history.
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
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.
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
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.
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
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).
Mostly yes. With a reliability score of 7.6 out of 10 based on 11 owner complaints filed with NHTSA, the 2021 BMW M340i is generally a sound vehicle. The areas to watch are listed in the top problem section above — most are budget items, not deal-breakers.
Should you avoid the 2021 BMW M340i?
The 2021 BMW M340i is acceptable, with specific caveats. Worth owning if you verify the specific issues below before you buy. The record behind that call: Reliability score 7.6/10 — above the segment average; 6 recall campaigns on file. This is our read of the federal complaint and recall data — not a substitute for a pre-purchase inspection.
What should I check before buying a used 2021 BMW M340i?
Inspect the engine first — it's the most-reported issue on this model, with 6 owner complaints filed. Average repair cost runs about $3,100 at an independent shop. Also confirm any open recalls have been completed by running the VIN, and ask for service records covering the problem areas listed above.
Is the 2021 BMW M340i a good used car to buy?
It scores 7.6 out of 10 on our NHTSA-based read of 11 owner complaints. The main thing to watch is engine. Priced fairly and clean on inspection, it's a reasonable used buy. Our data covers what this model is known for — pair it with a vehicle-history report on the VIN to see what that specific car has been through.
What's the most common problem on the 2021 BMW M340i?
Based on NHTSA records, the most-reported issue is engine, with 6 complaints filed. Average repair cost runs about $3,100 at an independent shop.
What's the most expensive thing that goes wrong?
The engine is one of the costlier repair items. Average repair cost runs about $3,100 at an independent shop. Catching early warning signs can sometimes extend life by 20–30,000 miles.
How do I check if my BMW M340i has open recalls?
Paste your VIN into the decoder at the top of this page. We pull live from NHTSA, so you'll see exactly which campaigns apply to your vehicle and whether the dealer has logged the fix. Recall repairs are always free regardless of mileage or warranty status.
Is an extended warranty worth it on a 2021 BMW M340i?
Math is straightforward: a quality service contract runs $1,800–3,500 over 3 years. With 11 complaints on file and the costliest repair averaging $3,100, one major failure more than pays for it. The catch is reading the contract — many providers exclude wear items and require pre-authorization, so cheaper plans are not always better value.
Recall and complaint data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database, last synced 3 days ago. Verify the raw federal record at
nhtsa.gov/vehicle/2021/BMW/M340i.
Editorial commentary written by ProblemsByVin contributors and reviewed by ASE-certified mechanics.
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