2021 Mercedes-Benz GLB 250 4MATIC

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 codes. Called NHTSA to report where they verified that the manufacturer had agreed to repair the issue and extended the waranty instead of doing a recall. Was advised to file report online because the dealership is now demanding payment to do the software update. Which was already verified see attached. A rail pressure sensor is a core engine management component that measures fuel pressure in the fuel rail, sends real-time data to the engine computer, and helps regulate fuel delivery. Rail Pressure Sensor system Fault code P019185 Stores in MED41 control unit. Available for Inspection

NHTSA ID

11753817

Incident

Jun 16, 2026

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 escalation path available is a buyback, meaning Mercedes cannot provide a timeline for the software fix. I am currently unable to safely drive my vehicle and am requesting this be investigated as a potential safety defect that may affect other 2021 Mercedes GLB 250 owners.

NHTSA ID

11742901

Incident

May 22, 2026

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. Cause Possible signal timing between EZS control unit and Transmission Control Unit (DKG) Remedy As of 7/15/2026, new SCN coding is available for the EZS control unit. IPR will advise to open a TIPS case for EZS (N73), this is due to GLA models requiring support for SCN coding procedure. GLB (X247) and CLA (118) No TIPS case necessary. 1. SCN coding of EZS Control Unit 2. Clear all faults and perform extended road test with multiple drive cycles GLA (H247) Special function password required. 1. Verify if special procedure Central Locking ‑ Development Data is present in EZS (figure 1) 2. Submit a TIPS case to the Powertrain Inbox with the following information: ‑ Initial Quick Test w/ freeze frame data ‑ IPR Result ‑ DKG Control Unit Log ‑ EZS Control Unit Log ‑ Initial EEPROM data ‑ EZS special procedure menu If the vehicle has had this LI performed and P24F100 has returned, please submit a TIPS case to the Powertrain Inbox.

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 accelerator pedal application. May occur in all drive modes. Cause Dual‑clutch transmissions (DCT) inherently exhibit more dynamic shifting behavior compared to other types of transmissions. This is due to the use of physical clutches for starting and gear changes. In certain situations, dynamic driving behavior can lead to a slight jerk sensation which is a normal technical characteristic of the transmission. A typical example is a "Change of Mind" situation: • The customer is coasting towards a red traffic light. • The traffic light turns green while the vehicle is still coasting. • The customer then presses the accelerator pedal. In these situations, a slight jerk may occur briefly because the transmission must quickly engage the appropriate gear and control the clutches accordingly. Since shift forks are responsible for engaging the gears during shifting, a slight shifting noise may also be noticeable. Please note driving programs S, S+, and M are designed to provide sportier vehicle behavior and are not optimized primarily for maximum comfort, so this operation may be more audible. Remedy Verify the customer's concern and confirm proper transmission operation. If no faults or abnormal operating conditions are identified by IPR (Intelligent Predictive Repair), no hardware replacement is necessary. Inform the customer that the transmission has been designed to provide direct gear engagement and responsive vehicle performance. Under certain operating conditions, brief shift sensations may be perceptible and are consistent with the operating characteristics of the dual‑clutch transmission

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 control for 8‑speed dual‑clutch transmission (DKG): P056300 The on‑board power supply voltage is too high. Cause An overvoltage condition is detected exclusively within the transmission control unit, storing fault P056300 once the measured voltage exceeds 16V. Remedy This LI applies if the freeze frame data for P056300 show a supply voltage between 15.75 to 16.50 volts, and no other control units report overvoltage. (figure 1) Long Term Resolution: Software resolutions have been released. Check validity and ensure your Xentry is updated with latest Addons before continuing: 1. Perform software update for Y3/14 ‑ Transmission control for 8‑speed dualclutch transmission (DKG) available software listed in Parts 2. Clear fault memory and perform final test drive If the customer complaint matches this LI and the software currently installed on the vehicle is not listed, please submit a TIPS case to the Powertrain inbox with the following information: ‑ Initial Quick Test w/ Freeze Frame Data ‑ DKG Control Unit Log ‑ Latest EEPROM data ‑ Screenshot of software availability

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 that the tailgate no longer opens as a result of a long press on the button, but by double‑clicking on the button instead. This reduces the likelihood of the button being activated accidentally or unintentionally. The recoding can be carried out as follows: 1. Add SA Code O19 into VeDoc (O for Oscar, not "zero") • an XSS ticket may be necessary to add the SA code 2. Perform SCN coding of EIS N73 control unit 3. Deactivate the vehicle key (a successful deactivation is indicated by the LED lighting up 2x briefly and then 1x for a long period). 4. Place the vehicle key in the storage compartment on the key symbol and turn on the ignition. IMPORTANT: all other vehicle keys must be outside the recognition range of the vehicle when doing this! Perform steps 3 and 4 successively for all vehicle keys. Notes: 6th, 7th and 8th generation keys can be deactivated as follows: Up to modification year 22/1 by double clicking the "Lock button" As of modification year 22/1, by press and holding the “Lock button", then double‑click the “Unlock button" at the same time. On model series 167, the storage compartment with the key symbol is located in the armrest. The SCN coding from the EZS is only transferred correctly to the vehicle key under the following conditions: Only one vehicle key is located in the vehicle, this key has been deactivated and it is positioned on the marking in the storage compartment for the data transfer. The costs for this adaptation are to be borne by the customer. For the newer BR 174, 178, 244, 248, 520, and 540, a software update must be initiated, as there is no way to perform SCN coding.

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 Tank Leakage Detection ("DMTL") on your vehicle from the original New Vehicle Limited Warranty of 4 years / 50,000 miles to 15 years/150,000 miles (whichever occurs first). This applies to the vehicle regardless of ownership. Why the Warranty extension? On certain Model Year 2018 - 2024 A / C / CLA / CLS / E / G / GLA / GLB / GLC / GLE / GLS / GT / S / SL Mercedes-Benz vehicles, under certain circumstances, the DMTL may trigger erroneous Diagnostic Trouble Code ("DTC") entries that may result in the illumination of the Check Engine Malfunction Indicator Lamp ("MIL"). Any repairs under this warranty extension must be performed by an authorized Mercedes-Benz dealership. • If your preferred authorized Mercedes-Benz dealership performs a diagnosis and confirms that your vehicle has the issue, the repair will be covered under this extended warranty and performed at no cost to you. • This extended warranty does not apply to any other components or conditions beyond the ones mentioned above, and standard warranty terms apply, including the exclusions with respect to extra expenses, as identified in the Service and Warranty Information booklet.

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 causes Remedy See attached diagnostic guide.