2021 Mercedes-Benz GLB 250 Fuel system Problems
- Complaints
- 2about this part
- Share
- 7%of 29 total for the year
- Median mileage
- —not reported
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 2 complaints about the fuel system of the 2021 Mercedes-Benz GLB 250, 7% of the 29 complaints for this model year.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“Engine locked up while driving out of state on the interstate. Vehicle lost all power and engine stopped functioning. Managed to pull over and stop the vehicle on the side of the interstate. Had truck towed to repair shop where they diagnosed connecting rod/crankshaft bearing failure, as well as lifter and cylinder misfire/failure on cylinder 7. Metal shavings were discovered in the oil, and engine locked up and cannot be repaired. …”
NHTSA complaint #11704669, filed 2025-12“In April 2025, my 2021 Mercedes-Benz GLB 250 (81,000 miles) suffered repeated engine issues caused by a cylinder head failure. The dealer attempted a cylinder head replacement, but during their own test drive after repairs, the engine completely seized and failed again on their property. This indicates a severe defect in the engine assembly that risks sudden power loss while driving, which could cause an accident. Prior to the failure, there were warning messages about misfires and rough idle. …”
NHTSA complaint #11668223, filed 2025-06Related service bulletins
- 11036999Aug 15, 2026Dear 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…
- 11035490Jul 31, 2026This NCU replaces the prior NCU issued on May 15, 2025, and contains additional MY 2023 and MY 2024 vehicles which are highlighted below.
- 11019016May 30, 2025In 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…
- 11018625May 15, 2025In our continuing efforts to ensure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our customers, Mercedes-Benz USA, LLC (“MBUSA”) is…
- 11014402Feb 21, 2025Complaint Customer-perceived problem: • Fuel gauge reading implausible • MIL ON (market-dependent) N118/3 Fault codes in control units FSCM_GEN4/5/6 • For these fault codes, the…
- 10253715Apr 23, 2024Check engine light active and FC P146364 Temp. and pressure sensor B4/7 is stored in Engine control unit and Fuel pump control unit. Software parameter in Fuel pump control unit…
- 10253706Apr 12, 2024IMPORTANT EMISSION EXTENDED WARRANTY INFORMATION In our continuing efforts to assure the proper performance of Mercedes-Benz products and to enhance the satisfaction of our…
Fuel system: other model years
Other parts of the 2021 Mercedes-Benz GLB 250
10 complaintsEngine
7 complaintsElectrical system
4 complaintsSuspension
4 complaintsBody and structure
3 complaintsTransmission and drivetrain
3 complaintsBack-over prevention (rear camera)
2 complaintsSteering
2 complaintsVisibility (wipers, defrost, mirrors)
2 complaintsWheels
2 complaintsAir bags
1 complaintsBrakes
1 complaints
← All problems reported for the 2021 Mercedes-Benz GLB 250
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 31, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology