AI Damage2021 Mercedes-Benz GLB 250 4matic: common problems
Owners of the 2021 Mercedes-Benz GLB 250 4matic filed 2 complaints with NHTSA, most often about engine and electrical system. The maker issued 60 service bulletins for this year. We found 2 repair videos on YouTube. Details by component below, with sources.
Key figures
- Owner complaints
- 2
- Technical service bulletins (TSB)
- 60
- YouTube repair videos
- 2
What fails most often
- 1 Engine 100% of all complaints
- 2 Electrical system 50% of all complaints
- 3 Fuel/propulsion system 50% of all complaints
- Engine: 2 complaints (100% of all); manufacturer bulletins for this component: 4.
- Electrical system: 1 complaints (50% of all); manufacturer bulletins for this component: 30.
- Fuel/propulsion system: 1 complaints (50% of all); manufacturer bulletins for this component: 2.
Symptoms owners describe
How many of the 2 NHTSA complaints mention each symptom (automatic count from complaint text; one complaint can mention several).
Components owners complain about
| Component | Owner complaints | involving a crash | Technical service bulletins (TSB) |
|---|---|---|---|
| Engine | 2 | 0 | 4 |
| Electrical system | 1 | 0 | 30 |
| Fuel/propulsion system | 1 | 0 | 2 |
| Structure | 0 | 0 | 7 |
| Powertrain | 0 | 0 | 5 |
| Steering | 0 | 0 | 5 |
| Visibility | 0 | 0 | 4 |
| Exterior lighting | 0 | 0 | 3 |
| Backover prevention | 0 | 0 | 2 |
| Suspension | 0 | 0 | 2 |
| Lane departure | 0 | 0 | 1 |
| Service brakes | 0 | 0 | 1 |
| Other | 0 | 0 | 4 |
What owners report
Short excerpts of NHTSA complaints in the original wording. These are owner statements not verified by NHTSA; personal data removed.
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.
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.
Comparison
By complaint count this model year ranks 19,885 of 36,659 model years in the NHTSA data (among the 46% least complained about).
On average one model year of the GLB 250 4matic has 2 complaints (7 years in the data). This year has 2, about average.
What to check before buying
- Engine. Cold start, unusual noises, oil leaks and engine codes.
- Electrical system. Scan all modules, test the battery and alternator, inspect connectors near the impact zone.
- Fuel/propulsion system. Fuel smell, leaks, rough running, fuel-system codes.
- Structure. Rails, pillars, panel gaps, signs of pulling or welding.
Manufacturer service bulletins
Bulletin titles as filed with NHTSA.
- Complaint Clanking noise from the area of the speakers in the doors
Cause Under analysis. Remedy To narrow down the cause, first of all remove the door trim. • If the noise continues to occur even with the door trim removed, then continue the diagnosis working towards the speaker and…
- Complaint Slight creaking noises when steering
Cause Noises may come from one or more sleeves of the horn contact plate. Remedy Remove the horn contact plate and check the sleeves for noise; see attached video. If necessary, apply lubricant to the sleeves.
- Complaint Repeat workshop visit for vehicle vibration while braking from 60MPH. NOTE
Although the symptom is similar to a tire or wheel vibration, it is usually readily noticeable that it is distinctly different if it happens at all times or only while braking. Cause Although the cause of the vibration…
- Complaint Radio station cover art does not refresh when switching stations
The UI continues to show the old station’s artwork instead of updating to the new one. Cause When a new station change request is triggered, a temporary glitch is causing the Head Unit application to fail to overwrite…
- Complaint Intermittent shift feel or thud/clunk noise perceived, such as a brief jerk or transmission…
Complaint Intermittent shift feel or thud/clunk noise perceived, such as a brief jerk or transmission reaction during certain driving situations. May be most noticeable when transitioning from a coasting condition to…
- Complaint Temporary no start condition with check engine light and multiple warning messages
When performing a quick test, the following fault code is stored in Y3/14 ‑ Transmission control for 8‑speed dual‑clutch transmission (DKG): P24F100 The wake‑up line of the control unit has a short circuit to positive…
- Dear Mercedes-Benz Owner
In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA is extending the warranty coverage for the Diagnostic Module for…
- Complaint Customers may report one or more of the following
• Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after ignition cycle When performing a quick test, the following fault code is stored in Y3/14 ‑ Transmission…
- Complaint Tailgate opens unintentionally
Cause Accidental or unnoticed activation of the button to open the tailgate on the vehicle key. EXAMPLE: when stored in trouser pocket, handbag etc. Remedy As of the 6th generation, the vehicle key can be recoded so…
- Complaint 1
General Diagnostic Tips 2. One or More PARK Sensor Activations 3. Red Ring Around Vehicle 4. "Active Parking and Parking Assist Inoperative" on Instrument Cluster 5. Cameras 6. Other Park Topics. Cause Various root…
- Complaint Customers may report one or more of the following
• Transmission malfunction message • Check engine light illuminated • Shifts into N • Concern disappears after ignition cycle When performing a quick test, the following fault code is stored in Y3/14 - Transmission…
- This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024…
This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below. In our continuing efforts to ensure the proper performance of Mercedes-Benz…
NHTSA lists 60 bulletins for this year; the 12 newest are shown here.
Repair videos
We do not copy videos: these are YouTube links credited to their authors. Amounts are as stated by the author and not verified by us.
Other years of this model
Questions and answers
What are the most common problems with the 2021 Mercedes-Benz GLB 250 4matic?
Owner complaints to NHTSA most often mention: engine, electrical system, fuel/propulsion system. Total complaints: 2. The most frequent symptoms in complaint texts: loss of power / limp mode (100%), warning lights, check engine (100%).
How many service bulletins (TSB) were issued for the 2021 Mercedes-Benz GLB 250 4matic?
NHTSA lists 60 manufacturer service bulletins for this year. A bulletin tells dealers how to diagnose or fix a known issue; it is not a recall.
Should I buy a 2021 Mercedes-Benz GLB 250 4matic from a US auction?
Owner complaints describe defects, not crash damage. Before bidding, check the components listed above and review the lot photos: VinWind builds a report of visible and hidden damage by VIN.
Other 2021 models
Read also
Sources: public NHTSA data (USA): service bulletins and owner complaints; YouTube: links to videos credited to their authors. Complaints are owner statements not verified by NHTSA, and describe defects rather than crash damage. Data updated 2026-11-06.