2021 Mercedes-Benz GLB 250 problems & reliability
28 owner complaints filed with NHTSA for the 2021 Mercedes-Benz GLB 250, alongside 11 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Unknown OR Other | 10 | 36% |
| Engine | 7 | 25% |
| Electrical System | 4 | 14% |
| Suspension | 4 | 14% |
| Power Train | 3 | 11% |
| Back Over Prevention | 2 | 7% |
| Fuel/propulsion System | 2 | 7% |
| Steering | 2 | 7% |
| Structure | 2 | 7% |
| Wheels | 2 | 7% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
All 16 reported components →Complaints by incident year
What owners report
“Family and I were driving on the interstate and heard a loud bang (like a shotgun) followed by immediate glass everywhere. The panoramic sunroof exploded. We had to drive 4 hours like this - lucky we didn’t jerk the wheel on the interstate with the noise. Absolutely sickening that this is so prevalent and Mercedes…”
Unknown OR Other · filed Apr 29, 2026
“When my car sits in the rain for long periods of time, while driving, it will automatically switch into neutral and give me a "transmission malfunction stop" & "service required do not shift gears visit dealer" sign on the dash. This has happened at least 7 times in 2 years since March 2024. The latest time it…”
Engine · filed Mar 3, 2026
“The component that appears to have malfunctioned is the front axle integral carrier (front subframe) and the related front suspension geometry, as the vehicle now exhibits a persistent pull to the left and degraded steering stability after the dealer replaced the front lower control arms, engine mounts, and performed…”
Suspension · filed Feb 20, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
213 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2021 Mercedes-Benz GLB 250. The 10 most recent:
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…
EW - DMTL · Warranty Program/Extension · issued Jul 31, 2026
Complaint CEL light on with no drivability concerns. Cause Signal timing error. Remedy 167, 465: SW has been released. Update the FSAM to the latest SW version. 290, 118, 243, 247: Software is still in development. This…
LI54.21-P-080326 · Service Bulletin/Repair Instructions · issued Jul 24, 2026
Complaint Hand detection system – malfunction / vehicles with code 266 Fault message in instrument cluster: "Active Emergency Stop Assist not available" "Active Lane Keeping Assist not available" "Active steering assist…
LI46.10-P-078012 · Service Bulletin/Repair Instructions · issued Jul 17, 2026
Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once in each instance when changing direction of travel. Note: Sound file in attachment Cause…
LI35.30-P-058566 · Service Bulletin/Repair Instructions · issued Jul 14, 2026
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…
LI82.60-P-080383 · Service Bulletin/Repair Instructions · issued Jul 8, 2026
Complaint CEL light on with no drivability concerns. Cause Signal timing error. Remedy 167: SW has been released. Update the FSAM to the latest SW version. 465, 290, 118, 243, 247: Software is still in development. This…
LI54.21-P-080326 · Service Bulletin/Repair Instructions · issued Jul 2, 2026
Dear Mercedes-Benz USA Dealers, The part numbers listed in the chart below should no longer be installed, and any existing stock must be returned to your facing PDC. The deadline for all dealer returns is no later than…
PSL-NCU Return Parts 6/19 · Other · issued Jun 19, 2026
Complaint Service code B1 displayed in the customer menu does not match the workshop code displayed in the workshop menu, e.g., 505 or 550A, which includes a service A. Cause The root cause is currently being…
LI00.20-P-080703 · Service Bulletin/Repair Instructions · issued Jun 12, 2026
Complaint After successful commissioning of the HERMES control unit (N112/9) with XENTRY Diagnosis DVD 03/2026, the message "SOS - service not activated" appears on the instrument cluster. In addition, the following two…
LI82.85-P-080507 · Service Bulletin/Repair Instructions · issued May 26, 2026
Complaint Noises from the area of the steering column. - Creaking - Squeaking - Chattering - Humming - Grinding Cause At present, there are no known noise problems with the steering column. Remedy Check surrounding area…
LI46.15-P-070510 · Service Bulletin/Repair Instructions · issued May 22, 2026
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2021 Mercedes-Benz GLB 250 has 11 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2021 Mercedes-Benz GLB 250?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.