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2021 BMW 4 Series problems, recalls and owner complaints
What the 2021 BMW 4 Series has been recalled for, how often it fails the UK MOT and what owners report, from official government data. Updated October 25, 2026.
- 5safety recalls
- 21owner complaints
- 1crash report
- 1fire report
- 6%fail the UK MOT
21 complaints, against an average of 31 for the other 10 BMW 4 Series model years.
Every BMW 4 Series model year with its number of owner complaints. Pick a year to compare.
What goes wrong with the 2021 BMW 4 Series?
The components named most often in the 21 owner complaints. One complaint can name several, so the shares can add up to more than 100%.
What symptoms do 2021 BMW 4 Series owners describe?
Found by reading the text of all 21 owner complaints. Tap a symptom for the answer, a real owner quote and any related recall.
Has the 2021 BMW 4 Series been recalled?
5 U.S. safety recalls. Repairs are free at a franchised dealer; some are done over the air.
Seat Belts 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.
Seat Belts 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).
Air Bags: Side/Window: Thorax BMW of North America, LLC (BMW) is recalling certain 2021 430i and M440i 4 Series Convertible vehicles. In certain side-impact crashes, the head-thorax air bag may not deploy as intended.
Risk: An air bag that deploys incorrectly can increase the risk of injury in a crash.
Fix: Dealers will update the software, at no charge. All affected vehicles are still in dealer inventory, and therefore no owner letters will be mailed. The recall began March 9, 2021. Owners may contact BMW customer service at 1-800-525-7417.
Back Over Prevention: Sensing System: Camera 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.
Electrical System: 12v/24v/48v Battery 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.
Is the 2021 BMW 4 Series recalled in the UK or Europe?
Recalls issued by the UK's DVSA and through the EU's Safety Gate system that cover this model and build period. European models can differ from U.S. ones, and "years estimated" means the recall gave no build dates, so confirm your own car with your registration or VIN.
UK DVSAReplace the Engine Starter Motor
Risk: The Safety Recall relates to the engine starter motor. The fault relates to the RSW22 starter RWT (reinforced water tightness). It was found that with RWT starters an increased abrasion of the magnetic contact can cause the growth of deposits at the lowest point of the relay interior. This in turn may increase the relay contact resistance resulting in false starts or even causing short circuits and possibly a thermal reaction. In case of a short circuit the possibility of a thermal event cannot be excluded. This may happen while attempting to start the vehicle or while driving due to vibrations causing a short circuit due to moving deposits.
Fix: On the affected vehicles the starter motor will be replaced with a variant by another supplier with a different design. Until the repair has been completed it is recommended to not leave the vehicle running unattended after starting the engine.
UK DVSAReplace the Engine Starter Motor
Risk: For affected vehicles there is a concern involving water ingress and corrosion to the starter motor for where a short circuit cannot be ruled out. It is strongly recommended to park the vehicle outdoors and not in the immediate vicinity of buildings until the repair has been carried out.
Fix: Replacement of the starter motor.
UK DVSAOn certain vehicles the Body Domain Controller (BDC) control unit may have an incorrect setting applied to it.
Risk: On certain vehicles the Body Domain Controller (BDC) control unit may have an incorrect setting applied to it.
Fix: Conduct a check of the settings and if necessary perform a reset on the BDC control unit.
UK DVSAUndetected EGR System leaks may cause thermal activity in the intake manifold
Risk: Undetected EGR System leaks may cause thermal activity in the intake manifold.
Fix: The engine management control unit (DDE) will be programmed with improved software incorporating the latest OBD functionality.
UK DVSAThe exhaust gas recirculation cooler may leak over time and cause thermal incident
Risk: The Exhaust Gas Recirculation cooler may leak over time and cause thermal incident.
Fix: On the affected vehicles the EGR cooler module will be replaced.
UK DVSAAffected vehicles may be fitted with brake discs which are not to specification
Risk: Affected vehicles may be fitted with brake discs which were not produced according to the specifications
Fix: On the affected vehicles the brake discs will be checked and if necessary replaced
UK DVSAThe battery cables on the 48v starter generator may not have been sufficiently secured during production
Risk: The battery cables on the 48V starter generator may not have been sufficiently secured during the production process.
Fix: Check the screw connection of the 48V positive / negative battery cables on the starter generator and rework if necessary.
EU Safety GateThe RSW22 starter with reinforced water tightness (RWT) may experience increased abrasion of the magnetic contact, causing deposits to…The RSW22 starter with reinforced water tightness (RWT) may experience increased abrasion of the magnetic contact, causing deposits to build up at the lowest point inside the relay. These deposits may increase relay contact resistance, leading to starting failures or short circuits. If a short circuit occurs, either when attempting to start the vehicle or while driving due to vibration-related movement of the deposits, it could cause a thermal event and increase the risk of fire.
Measures: Type of economic operator taking notified measure(s): Manufacturer; Category of measure(s): Recall of the product from end users; Date of entry into force: 07/07/2026
EU Safety GateWater may come into contact with the starter relay and gradually cause corrosion.This could affect the electrical connection inside the relay and make the engine difficult to start. It may also result in a short circuit and could cause the starter to overheat leading to a fire when the vehicle is in motion or when it is parked with the ignition off.
Measures: Type of economic operator taking notified measure(s): Manufacturer; Category of measure(s): Recall of the product from end users; Date of entry into force: Unknown
EU Safety GateThe screws which were used to assemble seatbelts and also on the rear seats of the vehicles concerned may not have been manufactured in…The screws which were used to assemble seatbelts and also on the rear seats of the vehicles concerned may not have been manufactured in accordance with specifications. In some cases, the screws in question cannot withstand extreme loads, which could increase the risk of injury in the event of an accident.
Measures: Type of economic operator taking notified measure(s): Manufacturer; Category of measure(s): Recall of the product from end users; Date of entry into force: Unknown
How often does the 2021 BMW 4 Series fail its MOT?
Why they failed: the share of failed tests with at least one fault in each area (a test can fail on several). Cars first registered in 2021, tested in Great Britain in 2023; first registration is usually, but not always, the model year. Source: DVSA anonymised MOT tests and results, Open Government Licence v3.0.
What do 2021 BMW 4 Series owners report?
12 of the 21 complaints, the most recent for the most-reported components, as the owners wrote them. NHTSA removes names and VINs; long reports are trimmed. CarHooq has not verified individual claims.
BMW dealer noted "clunk on accel" at 57,152 miles on RO #224018 under engine mounts. Dealer quoted $3,463.38 for engine mounts. I declined repair. Clunk on acceleration is still present at 60,700 miles. Same symptom as BMW Service Bulletin SIB 27-02-20 for 4 Series Drive jerking/shuddering from transfer case. Transfer case was serviced by non-BMW shop prior to my ownership (unknown fluid spec). Dealer documentation only notes clunk on accel and engine mounts/alignment. Requesting investigation as this matches known transfer case defect with lifetime fluid claim. Vehicle is just out of 4yr/50k…
The engine starter motor system failed, specifically involving an intermittent no-start condition related to a pinion starter line break / internal component defect. The vehicle and all original mechanical components are fully intact and available for professional inspection upon request. The engine starter motor system failed, specifically involving an intermittent no-start condition related to a pinion starter line break / internal component defect. The vehicle and all original mechanical components are fully intact and available for professional inspection upon request. The vehicle is…
I am seeing a lot of concerns regarding the seatbelt extenders, the buckle end pretensioner, seat wiring harness and the yellow box connectors that are where the main power and air bag SRS connections sit under the drivers seat. The seat harnesses are catching in the sliding track mechanism during forward and backward adjustments, isn't that a manufacturer error as the harnesses are only kept in place by plastic routing clips, which may or may not be there. I am just wondering if this should be looked at on the 2021 440i convertibles? I love the car but worry this is a safety issue forums are…
The recall was issued more than 8 months ago but the remedy is still not yet available, which is very concerning as the problem may cause the event of fire even when the vehicle is parked. Issued SEP 23, 2025 Description of Problem It is possible for water to contact and enter the engine starter. This could lead to corrosion which could cause a short circuit. Safety Risk This could increase the risk of a thermal event or fire during driving or even when the vehicle is parked and the ignition is off.
The engine Unknown The problem was confirmed by BMW as they sent me a notice. Unknown Unknown
I received a recall notice dated 9/23/2025. The recall is listed as URGENT safety issue that could cause a fire. The notice instructs not to drive the car or park in garage. It has been over 6 months now and there is still no fix. I am requesting the manufacture buyback my vehicle.
The contact owns a 2021 BMW 430I. The contact stated that the front driver’s side seat belt chest strap was shredded. The contact was concerned that the seat belt would not safely secure the driver in a crash. The contact stated that the shredded seat belt strap might have been caused by the seat belt strap touching the seat belt retractor while pulling the seat belt buckle up. The vehicle was taken to the local dealer who indicated that the seat belt needed to be replaced. The vehicle was not yet repaired. The manufacturer was notified of the failure, but no assistance was offered. The…
The contact called for the owner of the 2021 BMW 430I. The owner received notification of NHTSA Campaign Number: 25V636000 (Electrical System); however, the part to do the recall repair was not yet available. The local dealer was not contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure.
The component that malfunctioned is the engine starter relay, which is subject to an open BMW/NHTSA safety recall (issued September 2025) due to potential corrosion causing overheating, short circuits, and vehicle fire risk. The recall specifically advises parking the vehicle outside and away from structures until repaired. The vehicle is available for inspection upon request.My safety and the safety of my family were put at risk because the dealership (Capitol Nissan in San Jose) failed to disclose this critical fire-risk recall before or during the sale on January 4, 2026, despite it being…
The contact owns a 2021 BMW 430I. The contact stated while stopped at a traffic light, the light turned green; however, when the accelerator pedal was depressed, the vehicle failed to respond as intended. The contact stated that the power train warning light was illuminated. The contact turned off and restarted the vehicle, shifted to drive(D); however, the vehicle failed to respond. The contact had the vehicle towed to a dealer to be diagnosed. The dealer determined that the rear differential oil had leaked out causing the differential to seize. The contact was informed that the rear…
This automobile is designed with a seatbelt assembly which has an arm which reaches out to bring your your seatbelt. See pix. It is made with plastic and glue and is amazingly flimsy. I cannot believe that BMW created such a "cute" but flimsy design. It cannot withstand being used hundreds of time when the seatbelt is used. It broke (see pix). Now a rigid arm with a jagged edge comes out at eye level. Someone is going to become seriously injured!!!! BMW claims that this resulted from misuse and not faulty cheap design and wants me to pay for the repair!!!!!!! This entire assembly needs to be…
Pirelli Cinturato 7 all season 225/40R19 I found front and rear bump side wall tires and miles driven 5300 miles. I’m very concern about this issues
2021 BMW 4 Series: questions owners ask
Is the 2021 BMW 4 Series reliable?
NHTSA data alone cannot rate reliability, but it shows what owners reported. Owners filed 21 complaints with NHTSA about the 2021 BMW 4 Series; the most common categories were electrical system (7, 33.3%), engine (5, 23.8%), seat belts (4, 19%). There are 5 safety recalls. 1 complaint mentions a crash, 1 mentions a fire, 2 injuries were reported.
What are the most common problems with the 2021 BMW 4 Series?
Across 21 owner complaints filed with NHTSA, the categories mentioned most often are electrical system (33.3% of complaints), engine (23.8% of complaints), seat belts (19% of complaints), power train (9.5% of complaints), forward collision avoidance (4.8% of complaints). One complaint can name several components.
Does the 2021 BMW 4 Series have any recalls?
Yes. NHTSA lists 5 recalls for the 2021 BMW 4 Series; the most recent (campaign 23V584000, 2023-08-16) concerns Seat Belts. Recall repairs are free at a franchised dealer; check your VIN at nhtsa.gov/recalls.
Why does the seat belt not latch or retract properly in my 2021 BMW 4 Series?
3 of the 21 owner complaints NHTSA has on file for the 2021 BMW 4 Series (14.3%) describe seat belts not latching, retracting or locking. 2 related recalls exist: campaign 23V584000 (seat belts). The fix: Dealers will update the receiver audio module software, free of charge. One owner wrote: "I am seeing a lot of concerns regarding the seatbelt extenders, the buckle end pretensioner, seat wiring harness and the yellow box connectors that are where the main power and air bag SRS connections sit under the drivers seat." (NHTSA complaint 11753304, July 2026). Recall repairs are free at a dealer; check your VIN at nhtsa.gov/recalls.
Check your own 4 Series
Counts are a starting point, not a verdict: popular models collect more complaints because more of them are on the road, and NHTSA does not verify individual reports. To see whether a recall is still open on your car, enter your VIN at nhtsa.gov/recalls (U.S.) or your registration at check-vehicle-recalls.service.gov.uk (UK). Had a safety problem? Report it to NHTSA; complaints are what trigger investigations and recalls.
Data: NHTSA Office of Defects Investigation recall and complaint databases (public domain), DVSA anonymised MOT results (Open Government Licence v3.0), DVSA vehicle recalls (Open Government Licence v3.0), EU Safety Gate alerts (© European Union), retrieved October 25, 2026. Model year 2021 only; combines NHTSA's entries for 4 SERIES and M440I.