2021 Mercedes-Benz GLB 250 Engine Problems
- Complaints
- 7about this part
- Share
- 24%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 7 complaints about the engine of the 2021 Mercedes-Benz GLB 250, 24% 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.
“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 happened was last week. I will get into my car after a day at work, when it has been raining, drive a few miles and the car will switch into neutral and display those signs. This is incredibly dangerous for my safety as the driver, any passengers and any other cars on the road. …”
NHTSA complaint #11721700, filed 2026-03“We purchased a brand new Mercedes GLB in January 2021, I noticed the car started to shake. On our way leaving Zion National Park, the car started shaking really hard and the engine light turned on. The car wouldn't accelerate. We had to pull over on the side of the road. We barely made it to the dealer in St. George, Utah, with the car shaking the entire time. We met with Ryan Poleszak the service adviser, and he said that he has seen this problem several times with Mercedes 4-cylinder engines in GLB, GLA, and C-class models in the past, and it looks like the car needs a new engine. …”
NHTSA complaint #11467987, filed 2022-06“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 2025-06“Jerking and loud noise from the engine after attempting to accelerate from a red light stop. Vehicle is idling very roughly and almost sounds like a diesel engine. Check engine light came on. Inspection at the dealership found multiple faults for camshaft positions deviating from the specified value. When the oil filter was removed, the shop reported finding some metal particles in the oil. The conclusion was that a mechanical fault caused a metal part in the engine to brake and clog up the engine. …”
NHTSA complaint #11665355, filed 2025-06Related service bulletins
- 11034506Jul 2, 2026Complaint 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…
- 11034064Jun 19, 2026Dear 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…
- 11030302Mar 27, 2026Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to mixture formation, injector quantity…
- 11028267Feb 2, 2026Complaint -Check engine light illuminated. -Engine runs rough. -Poor shifting or jerking when accelerating. -Fault codes stored related to mixture formation, injector quantity…
- 11021897Aug 4, 2025Complaint: Check engine light comes on when driving/starting the vehicle. No drivability concerns. Cause: Communication error in G1/3 - 48 V on-board electrical system battery…
- 11018215May 2, 2025Mercedes-Benz AG, the manufacturer of Mercedes-Benz vehicles, has determined that on certain subject vehicles, the SCN coding in the Belt-driven Starter Alternator (BSA) control…
- 11008712Oct 4, 2024Complaint Check engine light on. One of the below fault codes is current in the engine control module (N3/10). P04DB29, P04DB31, P04DB79 Cause Open circuit or high resistance to…
- 11008056Sep 16, 2024Complaint Check engine light on. Fault code P207273 - "Throttle actuator valve is blocked due to ice" stored. Engine may crank and not start. Fault code P210185 may also be…
- 11005313Jul 17, 2024Complaint Check engine light on and fault code P019185 current or stored in MED41 control unit. Adaptation and misfire faults may also be stored. Vehicle may enter limp home…
Engine: other model years
Other parts of the 2021 Mercedes-Benz GLB 250
10 complaintsElectrical system
4 complaintsSuspension
4 complaintsBody and structure
3 complaintsTransmission and drivetrain
3 complaintsBack-over prevention (rear camera)
2 complaintsFuel system
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