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2021 Mercedes-Benz GLB-Class problems, recalls and owner complaints
What the 2021 Mercedes-Benz GLB-Class has been recalled for, how often it fails the UK MOT and what owners report, from official government data. Updated October 25, 2026.
- 8safety recalls
- 7owner complaints
- 0crash reports
- 0fire reports
- 4%fail the UK MOT
7 complaints, against an average of 16 for the other 6 Mercedes-Benz GLB-Class model years.
Every Mercedes-Benz GLB-Class model year with its number of owner complaints. Pick a year to compare.
What goes wrong with the 2021 Mercedes-Benz GLB-Class?
The components named most often in the 7 owner complaints. One complaint can name several, so the shares can add up to more than 100%.
Has the 2021 Mercedes-Benz GLB-Class been recalled?
8 U.S. safety recalls. Repairs are free at a franchised dealer; some are done over the air.
Latches/Locks/Linkages: Doors: Lock Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2020-2021 CLA, 2019-2022 A-Class, 2022-2023 C-Class, 2024 CLE, 2020-2026 GLA/GLB, and 2023-2024 GLC vehicles. Please refer to MBUSA's recall report for specific model information. The micro-switch in the driver's door lock may corrode and fail to detect an open door, preventing the electronic parking brake or "Auto-Park" feature from engaging automatically. This may result in a vehicle rollaway.
Risk: A vehicle rollaway increases the risk of a crash or injury.
Fix: Dealers will replace the driver's door lock, free of charge. Owner notification letters are expected to be mailed September 18, 2026. This will be a phased campaign, with the remedy becoming available in different phases based on model and model years. Owners may contact MBUSA customer service at 1-800-367-6372. Vehicle Identification Numbers (VINs) involved in this recall will be searchable on NHTSA.gov beginning July 31, 2026.
Electrical System: SoftwareOver-the-air fix Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2017-2022 CLA-Class, GLA-Class, GLE-Class, GLS-Class, SLC-Class, A-Class, AMG GT-Class, C-Class, E-Class, S-Class, SL-Class, GLC-Class, CLS-Class, GLB-Class, and G-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. An error in the communication module's SIM card software can cause a mobile network connection failure, disabling the emergency call (eCall) system.
Risk: A disabled eCall system would prevent a vehicle occupant from contacting the emergency services call center in an emergency, potentially delaying emergency responders and increasing the risk of injury.
Fix: The communication module software will be updated through an Over-the-Air (OTA) update or by a dealer, free of charge. Owner notification letters were mailed July 8, 2022. Owner notification letters will be mailed in phases, on July 8, 2022, May 17, 2024, July 29, 2024, and September 27, 2024. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's numbers are for this recall is 2022060005 and 2023110006.
Back Over Prevention: Display Function Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2018-2021 CLA-Class, GLE/GLS-Class, A-Class, C-Class, E-Class, E-Class Coupe/Convertible, GLA/GLB-Class, GLC-Class, and CLS-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. The rearview camera may not display the rearview image due to a software error. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 111, "Rear Visibility."
Risk: An inoperable rearview camera display reduces the driver's rear view, increasing the risk of a crash.
Fix: Dealers will update the rearview camera software, free of charge. Owner notification letters were mailed July 15, 2022. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2022060007.
Suspension: Front Mercedes-Benz USA, LLC. (MBUSA) is recalling certain 2021 AMG GLB35, 2019-2020 A220, and 2020 GLB250 vehicles. The integral carrier that supports the front axle may corrode, causing it to fail.
Risk: Front axle carrier failure may result in a loss of steering control, increasing the risk of a crash.
Fix: Dealers will inspect and replace the integral carrier, as necessary, free of charge. Owner notification letters were mailed July 29, 2022. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2022070009.
Air Bags: Side/Window Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021 GLB 250 and AMG GLB 35 vehicles. The driver-side window air bag may not have been mounted correctly to the lower area of the A-pillar. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 226, "Ejection Mitigation."
Risk: The driver-side window air bag may not function properly during a crash, increasing the risk of injury.
Fix: Dealers will inspect the mounting of the driver-side window air bag and repair it as necessary, free of charge. Owner notification letters were mailed December 2021. Owners may contact MBUSA customer service at 1-800-367-6372.
Back Over Prevention: Sensing System: CameraOver-the-air fix Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2019-2021 CLA-Class, GLE/GLS-Class, A-Class, E-Class, E-Class Coupe and Convertible, GLA/GLB-Class, GLC-Class, CLS-Class, and AMG GT-Class 4-door Coupe vehicles. Please refer to MBUSA's recall report for specific vehicle model details. The MBUX multimedia system software may cause the display to remain black, or reboot after startup. This could result in the rearview camera image not displaying properly. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 111, "Rear Visibility."
Risk: A backup camera that displays a blank image reduces the driver's rear view, increasing the risk of a crash or injury.
Fix: The multimedia system software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. Owner notification letters were mailed beginning June 28, 2021. Owners may contact MBUSA customer service at 1-800-367-6373. MBUSA's number for this recall is 2021050012.
Structure: Body: Tailgate Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2021 GLB35 AMG, and 2020-2021 GLB250 vehicles. The side spoilers on the tailgate might not have been installed correctly, allowing them to detach.
Risk: Detached spoilers can create a road hazard, increasing the risk of a crash or injury.
Fix: MBUSA will notify owners, and dealers will inspect and, if necessary, replace the side spoilers, free of charge. Owner letters were mailed July 2, 2021. Owners may contact MBUSA customer service at 1-800-367-6372. MBUSA's number for this recall is 2021050009.
Electrical System: SoftwareOver-the-air fix Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2016 - 2021 CLA-Class, GLA-Class, GLE-Class, GLS-Class, SLC-Class, A-Class, GT-Class, C-Class, E-Class, S-Class, CLS-Class, SL-Class, B-Class, GLB-Class, GLC-Class, and G-Class vehicles. Please refer to the Part 573 report for specific vehicle model details. The software design of the communication module may fail to communicate the correct vehicle location for the emergency call system (eCall) in the event of a crash.
Risk: Failure of the eCall system may result in emergency responders being dispatched to the wrong location, increasing the risk of injury following a crash.
Fix: MBUSA will notify owners, and the communication module software will be updated by a dealer, or through an over-the-air (OTA) update, free of charge. The recall began March 12, 2021. Owners may contact MBUSA customer service at 1-877-762-8267. MBUSA's number for this recall is 2021020025.
Is the 2021 Mercedes-Benz GLB-Class 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 DVSASRPC2404 – Backup function of steering software
Risk: On affected vehicles the backup function of the steering software might not meet specifications. As a result the steering power support might be impaired and a loss of steerability cannot be ruled out.
Fix: Update the software of the electric steering on the affected vehicles.
UK DVSAOn affected vehicles the corrosion protection of the integral carrier of the front axle might not be sustained over the lifetime of the…On affected vehicles the corrosion protection of the integral carrier of the front axle might not be sustained over the lifetime of the vehicle.
Risk: On affected vehicles the corrosion protection of the integral carrier of the front axle might not be sustained over the lifetime of the vehicle.
Fix: Replace the front axle carrier.
UK DVSAMechanical damage to the ESP unit
Risk: The Electronic stability program (ESP) unit might be mechanically damaged.
Fix: Replace the ESP unit on the affected vehicles.
UK DVSAThe level sensor linkage on the rear axle might not have been installed correctly
Risk: The level sensor linkage on the rear axle might not have been installed correctly.
Fix: Check the level sensor linkage on the affected vehicles and install it correctly if necessary.
UK DVSAThe crankshaft might not meet specifications
Risk: On certain vehicles with a 4-cylinder Diesel engine the crankshaft might not meet specifications.
Fix: Replace the engine on the affected vehicles.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe behaviour of the emergency call system might not meet specifications
Risk: The behaviour of the emergency call system might not meet specifications.
Fix: Update the software of the communication module for the emergency call system.
UK DVSAThe front fender wheel arch covers might not have been mounted according to specifications
Risk: The wheel arch covers on the front fenders might not have been mounted according to specifications.
Fix: Check the mounting of the front wheel arch covers on the affected vehicles and correct their installation if necessary.
UK DVSAThe side spoilers at the tailgate may not have been mounted to specifications
Risk: The side spoilers at the tailgate might not have been mounted according to specifications.
Fix: Check the mounting of the side spoilers and replace them if necessary.
UK DVSAThe communication module may be deactivated
Risk: The communication module may be deactivated
Fix: Carry out a check of the configuration of the communication module on affected vehicles and if necessary activate the communication module.
EU Safety GateThe steering software may not correctly activate the fallback level in the event of a hardware failure.This could affect the power steering assistance and lead to the loss of steering capacity, increasing the risk of an accident.
Measures: Type of economic operator taking notified measure(s): Manufacturer; Category of measure(s): Update of the electric steering software; Date of entry into force: Unknown; 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 Electronic Stability Program (ESP) unit might be damaged, moisture can reach the internal components leading to a short circuit,…The Electronic Stability Program (ESP) unit might be damaged, moisture can reach the internal components leading to a short circuit, increasing the risk of fire and/or cause the ESP functions (e.g. vehicle stability control, anti-lock braking systems) to be disabled, increasing the risk 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
EU Safety GateImproper torque of the screws on the brake caliper housing can cause the screw connections to become loose.As a result, the braking performance would be reduced and components of the brake caliper may be lost, increasing the risk of accidents.
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 GateCertain vehicles might not have been equipped with the version of the driver airbag specified for the vehicle in question.This can result in incorrectly deployment of the airbag or break away of the airbag module from the steering wheel into the interior of the vehicle. This will 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
EU Safety GateDue to inadequate corrosion protection, the integral subframe of the front axle may corrode, which could impair its operational strength…Due to inadequate corrosion protection, the integral subframe of the front axle may corrode, which could impair its operational strength and the connection of other components. This could have an impact on the steering capability of the vehicle, increasing the risk 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
EU Safety GateThe front wheel-arch covers may not have been attached correctly.As a result, a wheel-arch cover could detach completely while the vehicle is in motion, increasing the risk 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
EU Safety GateThe side spoilers on the boot lid may not be properly affixed.As a result, a spoiler could detach completely while the vehicle is in motion, increasing the risk 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
EU Safety GateThe oil-supply pipe on the turbocharger may leak.As a result, engine oil could leak onto the under-body paneling and from there onto the road, posing a risk to the following traffic.Moreover, leaking engine oil might come into contact with hot components in the engine compartment, increasing 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: Unknown
How often does the 2021 Mercedes-Benz GLB-Class 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 Mercedes-Benz GLB-Class owners report?
7 of the 7 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.
As I was driving down road car began to lose power, check engine light came on and car went into limp mode. Car was towed to nearest repair shop where analysis was made. I was advised to take to dealership for repair. Advised that there was a service campaign issued by the manufacturer on GLB class with M260 motors. See attached report. Took car to MB dealer and informed that an update to the ECU was needed but not available at this time. See attached report. Returned home to PA called Mercedes main office Customer service to check warranty and coverage yes it covered once dealer verifies…
While driving on the highway at 70mph my transmission malfunction warning light illuminated in red and my vehicle went into limp mode, creating a life threatening safety defect at highway speeds. I immediately took the vehicle to Mercedes Benz of Pittsburgh. The dealer's own diagnostic tech notes stated 'software is in preparation for concern' confirming this is a known safety defect on Mercedes' end. The dealer was unable to replicate the concern or produce stored fault codes but acknowledged software is actively being developed to address this issue. I contacted MBUSA who confirmed the only…
The contact owns a 2021 Mercedes-Benz AMG GLB35. The contact stated that while reversing down the driveway at approximately 4 MPH, the contact turned the steering wheel to the left and the vehicle started losing motive power. The contact stated that the RPMs were extremely high and the vehicle almost stalled. The contact stated no warning light was illuminated. The contact stated that the failure was intermittent and occurred at slower speeds between 3 and 6 MPH. The contact had taken the vehicle to a local dealer, where it was diagnosed and determined that the driver's side front axle had…
On 4/13/25 while driving my car on the highway, along with my 2 young children, I began to hear what initally sounded like a "flapping" noise. I rolled the windows down and after a minute or 2 the sound got lounder. There was never a warning or any type of safety icon that appeared on the control panel, nor any driving performance issue before hand. Shortly after the initial noise I could tell the car was struggling to accelerate. I wasn't near an exit during this time and began to panic in fear the car would shut down and I had no safe place to pull over on that stretch of highway. The noise…
The contact owned a 2021 Mercedes-Benz GLB35. The contact stated while driving at 35 MPH, the brake pedal was depressed; however, the vehicle failed to stop as intended. There was no warning light illuminated. The contact stated that neither the dealer nor an independent mechanic was contacted. The vehicle was not diagnosed or repaired. The contact stated that the vehicle was serviced months before the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 52,000.
I was driving home on a residential street at approximately 30 MPH. I heard a loud pop or bang sound coming from the top middle area of my windshield. I checked for any windshield damage, observed none. I thought the whole noise strange as nothing had hit my car or windshield. A couple days later I noticed that the glass panel between the windshield and sunroof, was completely shattered, with a horizontal crack running across the panel. I also noticed that the framing between the panel and windshield was not right. It sort of was "popped" outward. There was no warning regarding this failure. I…
The contact owns a 2021 Mercedes-Benz AMG GLB35. The contact stated he became aware that 3 out of 4 of the wheel-hub caps were missing. The contact called the local dealer and made them aware of the failure. The vehicle was not diagnosed or repaired. Upon investigation, the contact associated the failure with NHTSA Campaign Number: 20V800000 (Wheels) however, the VIN was not included. The manufacturer had not been informed of the failure. The failure mileage was approximately 22,000. Consumer is still waiting for trim replacement.
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2021 Mercedes-Benz GLB-Class: questions owners ask
Is the 2021 Mercedes-Benz GLB-Class reliable?
NHTSA data alone cannot rate reliability, but it shows what owners reported. Owners filed 7 complaints with NHTSA about the 2021 Mercedes-Benz GLB-Class; the most common categories were engine (3, 42.9%), electrical system (1, 14.3%), fuel/propulsion system (1, 14.3%). There are 8 safety recalls.
What are the most common problems with the 2021 Mercedes-Benz GLB-Class?
Across 7 owner complaints filed with NHTSA, the categories mentioned most often are engine (42.9% of complaints), electrical system (14.3% of complaints), fuel/propulsion system (14.3% of complaints), hydraulic (14.3% of complaints), power train (14.3% of complaints). One complaint can name several components.
Does the 2021 Mercedes-Benz GLB-Class have any recalls?
Yes. NHTSA lists 8 recalls for the 2021 Mercedes-Benz GLB-Class; the most recent (campaign 26V481000, 2026-07-24) concerns Latches/Locks/Linkages: Doors: Lock. Recall repairs are free at a franchised dealer; check your VIN at nhtsa.gov/recalls.
Check your own GLB-Class
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 AMG GLB35 and GLB-CLASS.