2021 Mercedes-Benz GLC 300

The contact owns a 2021 Mercedes-Benz GLC300. The contact stated that while driving 5 MPH, the vehicle stalled and lost motive power, with the check engine warning light illuminated. The vehicle was able to be restarted. The vehicle was taken to a service center, and the contact was provided DTC: P07B7. The contact was informed that the failure was associated with an internal transmission or software programming failure. The contact was informed that the transmission needed to be replaced and was referred to the dealer for additional assistance. The vehicle was scheduled for an appointment with the dealer. The failure mileage was approximately 75,000.

NHTSA ID

11775750

Incident

Oct 25, 2026

Mileage

75,000 mi

The contact owns a 2021 Mercedes-Benz GLC 300. The contact stated while driving 10 MPH, the blind spot assist detection feature failed to function as intended. The contact stated while inspecting the vehicle, the contact confirmed that the blind spot assist feature was enabled. In addition, the failure occurred after the vehicle was taken through the car wash. The contact's vehicle crashed into another vehicle. The vehicle was driven to the residence. The contact sustained pain to the right shoulder, arm and hand. The manufacturer was made aware of the failure and a case was filed. The failure mileage was approximately 26,000.

NHTSA ID

11769131

Incident

Oct 3, 2026

Mileage

26,000 mi

I own a 2021 Mercedes-Benz GLC 300. The vehicle developed moisture/condensation in the headlamp, and the affected headlamp subsequently failed. I took the vehicle to RBM of Alpharetta, an authorized Mercedes-Benz dealership. I was advised that corrosion was found in the affected headlamp and that the headlamp assembly requires replacement. On September 8, 2026, the dealership provided a repair estimate of $3,387.33. The vehicle had approximately 84,769 miles. Mercedes-Benz previously issued NHTSA Recall 22V-261 / Campaign 2022050005 for certain 2021 GLC-Class vehicles because headlamp electrical connections may not have been sufficiently watertight, allowing moisture intrusion that could cause headlamp failure. My vehicle is the same year and model and is experiencing headlamp failure involving moisture and corrosion, but Mercedes-Benz states that my VIN is not included in the recall population. Mercedes-Benz Customer Care opened Case 23963515 and has declined coverage to date. I am concerned that my vehicle may be experiencing the same or a substantially similar moisture-intrusion defect as vehicles covered by Recall 22V-261. A failed headlamp reduces nighttime visibility and presents a safety concern. I am requesting that NHTSA review whether similar headlamp moisture intrusion, corrosion, and failure may be occurring in additional 2021 Mercedes-Benz GLC 300 vehicles outside the original recall population.

NHTSA ID

11763616

Incident

Sep 11, 2026

My vehicle is experiencing moisture intrusion caused by a defective headlight housing seal. The water intrusion has resulted in a short circuit and failure of the turn signal module within the headlamp assembly. I am aware of NHTSA Safety Recall 22V-261, which addresses a substantially similar defect involving inadequate watertight sealing of the headlamp assembly that can allow moisture intrusion and lead to headlamp electrical failure. My vehicle is experiencing the same type of moisture intrusion and resulting electrical failure described in that recall. Because this failure appears consistent with the known safety-related defect identified by NHTSA, I am requesting that the vehicle and affected headlamp assembly be evaluated for recall-related or manufacturer-assisted repair rather than treated solely as a routine out-of-warranty component failure.

NHTSA ID

11763491

Incident

Sep 2, 2026

My 2021 Mercedes-Benz GLC 300 is not currently included in NHTSA Recall 22V-261 / Mercedes-Benz Campaign 2022050005, but my vehicle is experiencing substantially the same defect described in that recall. Moisture/water entered the left headlamp assembly/electrical connection, resulting in condensation/water accumulation and damage/corrosion around the headlamp electrical module/connector. The headlamp system subsequently malfunctioned. Recall 22V-261 describes a condition where the headlamp electrical connection may not be watertight, allowing moisture ingress and potentially causing headlamp failure. My vehicle appears to exhibit the same condition even though my VIN is excluded from the recall population. I am requesting that NHTSA review whether the affected population for Recall 22V-261 may need to be expanded.

NHTSA ID

11762288

Incident

Aug 28, 2026

The vehicle is experiencing an intermittent, sudden, and life-threatening drop into "limp home mode" while driving, creating an severe speed differential with surrounding traffic.First Incident (50,584 miles): The vehicle entered limp mode. Authorized Mercedes service center scanned the car, confirming Fault Code P019185 (Rail pressure sensor malfunction / signal above permissible limit value). The dealer applied an Engine Control Module software patch under Mercedes TSB LI07.70-P-078047.Second Incident (53,695 miles): Less than 3,000 miles later, the exact same sudden powertrain failure recurred. The vehicle drastically lost propulsion power immediately after exiting a high-speed freeway, leaving the driver in an incredibly vulnerable, unsafe position.The manufacturer's documented software remedy has completely failed to fix the underlying powertrain defect, leaving a known hardware component failure unaddressed while actively endangering vehicle occupants.

NHTSA ID

11760688

Incident

Aug 29, 2026

While the vehicle was being operated normally, it caught fire. We were driving on a summer day in August. Conditions were humid, with temperatures in the mid-80s. The vehicle was on the return leg of an approximately 30-mile drive. Traffic was somewhat heavy, with speeds generally below 20 mph and occasional stops. We first noticed a slight burning smell, followed shortly afterward by a distinct puff of white smoke coming from under the hood on the passenger side, near the windshield. We immediately decided to stop the vehicle and get out. Within approximately 30 seconds, we observed the first visible flames. Within about one minute, the fire had spread rapidly and the vehicle was engulfed in flames. By approximately 3½ minutes, the entire front half of the vehicle had been destroyed by the fire. Parts of the vehicle were blown off during the fire, with some debris traveling across the roadway and into the nearby woods. Fortunately, there were no injuries because we recognized the danger and exited the vehicle quickly.

NHTSA ID

11760363

Incident

Aug 4, 2026

While driving in my neighborhood at 25 MPH, my Mercedes GLC300 suddenly lost power and the check engine light illuminated. My car would no longer exceed 25-30 MPH, but I drove it straight to the dealership and they said it was a faulty cylinder head and will cost $10,000 to fix! After intense negotiations, they agreed to fix it for $4,205.58, which was better, but still, that’s a lot to pay for a manufacturer’s defect! My car is a 2021 with only 67,540 miles on it.

NHTSA ID

11739133

Incident

Jan 2, 2025

Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process. Cause As part of the on‑going quality monitoring process and associated quality and damaged part appraisals, a high number of ineffective repairs have been discovered. Such ineffective repairs have a negative impact on all those involved. For the customer, it means high costs and long repair times and for the dealer, it may result in the warranty claim being rejected. Remedy General note: IPR is available for: ‑ NAG3 Classic (automatic transmission 725.0) ‑ NAG3 Classic ‑ AMG sport model (AMG 43 and AMG 53 with converter, automatic transmission 725.0) ‑ NAG3 Classic ‑ Hybrid (automatic transmission 725.0) ‑ NAG3 Classic ‑ AMG 63 (automatic transmission 725.0) ‑ NAG3 MOPF ISG2 (automatic transmission 725.1) ‑ NAG3 MOPF Hybrid (automatic transmission 725.1) ‑ NAG3 MOPF AMG sport model (AMG 53/AMG 53e with ISG48V2 & converter /hybrid, automatic transmission 725.1) ‑ NAG3 MOPF AMG 43/63 with engine 139/177 (automatic transmission 725.1) Steps for the Service Advisor: Important: The more information and detail that can be given to the workshop about the complaint, then the more effective the subsequent diagnosis with IPR can be. To this end, a detailed service reception questionnaire has been provided to help the Service Advisor ask the right questions about the complaint. ‑ Ask precise details about the customer complaint and the conditions and context. ‑ Fill out the service reception questionnaire (please see WIS document: OF27.00‑P‑3000‑05A) for customer complaints in detail and forward it to the workshop. Operation steps for the workshop employee: 1. Perform quick test 2. Access the transmission control unit via XENTRY Diagnosis 3. Select "A customer complaint has been received" and carry out all subsequent operation steps (IPR diagnosis path). 4. The IPR repair instructions are displayed, Carry out the IPR repair instructions without performing any further diagnostic or repair steps. ‑ Important: The IPR repair instructions are binding and must be carried out. Differing repairs are possible; such repairs must be documented in XENTRY in free text. Please observe the information regarding the IPR diagnosis process in XENTRY. Conventional diagnosis and subsequent appropriate repairs are only permitted if IPR does not specify any repair instructions. Invoicing for the guided IPR steps: Operation item 27‑0640 and 0.1 hours Notice regarding warranty: The use of IPR in association with warranty claims is mandatory! If the IPR repair instructions are disregarded without justification, the warranty claims may be rejected and/or are subject to debit. IPR will provide a measure to repair the vehicle based on various data sources (EEPROM, fault codes, etc). Please consider the vehicle maintenance record of the vehicle. For warranty and goodwill repairs, the transmission ECU test log and/or IPR test result must be uploaded into Paperless XENTRY Diagnosis (pXD) . If repair is being determined based of oil pan condition pictures of oil pan MUST be provided to warranty as justification. ·Tamper‑proof documentation: The IPR repair instructions are stored in the control unit log. Please file this document in a tamperproof manner ‑ either in digital form or as a hard‑copy printout and also enclose a printout with the damaged part. In this regard, please comply with the country‑specific warranty requirements of the MPC/general distributor.

A software update will be performed that provides enhancements to the robustness and system stability of the communication module. The update is free of charge and runs in the background, which takes about 8 minutes to install. During this time, the vehicle can be driven without any restrictions, and the new software will be active with the next ignition cycle. Remedy MBUSA will conduct an OTA service campaign. Remote software updates are automatically downloaded and installed in the customer’s vehicle free of charge and do not require a dealer visit.

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 is most likely due to excessive lateral runout on the rotor or hub/wheel bearing, the system as a whole needs to be checked for other possible contributors. 1. Prior collision damage. 2. Excessive vehicle sitting times without rotating components. 3. Wheel bearing/hub lateral runout. 4. Wheel mating interface has been overtightened (did not follow WIS torque procedures). 5. Mating interfaces have been excessively modified (painted, gouged, bent, etc...). Remedy Read through the entire attached worksheet prior to performing. After performing, please review the final page and perform work accordingly. NOTE: This document is not pre‑authorization or otherwise dealing with warranty. This is intended for diagnostic purposes only. If there are any questions on how to proceed OR The work sheet has been performed and the vehicle has returned with the same concern. Please perform the measurements as seen in the worksheet again and open a TIPS case to the Body, Chassis, and Entertainment team.

Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick test. When accelerating with light load, vibrations or jolting sensation may come from the drivetrain. It may be mistaken for a harsh shift. Cause Modified oil quality of the transfer case over time Remedy 1. Check initial quick test for faults in the following control units. N45 or N15/7 ‑ All‑wheel drive (ARS) N127 ‑ 'Drivetrain' (PTCU) control unit Y3/8 ‑ Transmission control for 9‑gear transmission (VGS) N3/10 ‑ Engine electronics for combustion engine If faults are present: Process them as per the guided test in Xentry. If no faults are present: 2. Check the transmission oil level If the oil level is correct: 3. Unplug the connector for the transfer cases control unit and reassess the vehicle on a subsequent test drive If the complaint no longer occurs with the control unit disconnected: 4. Perform an oil change of the transfer case according to WIS specifications ‑ Collect an oil sample of the original fluid 5. Complete all transfer case Tech‑in processes located under VG Control Unit > Adaptations ‑ Resetting the oil service data ‑ Calibration of N15/7 5. Perform road test of vehicle to bring transmission to operating temperature (>60C ) 6. Operate vehicle in full circle with steering at full lock ‑ 5x to the left ‑ 5x to the right Return the vehicle to the client and request they drive the vehicle for at least 200 miles and return if the concern is not resolved. The extended drive will ensure the clutches are properly conditioned with the new oil and should resolve the concern. If this LI has already been applied to the vehicle, please submit a TIPS case to the Powertrain inbox with the following information: ‑ Initial quick test with fault freeze frame data ‑ Initial transmission EEPROM data ‑ VGS and Transfer Case Control Unit Log (N45 or N15/7) ‑ Special Acquisition Data .txt file (Transfer Case Control Unit > Special Procedures > Procedures for support queries to market support > Special Data Acquisition) ‑ Photo of the original oil condition ‑ What color was the fluid drained from the transfer case before the oil change? ‑ Was an oil sample collected, and can you provide a photo of the original fluid? ‑ What color and part number fluid was used during the oil change? ‑ How far was the vehicle driven after?

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 if necessary, create a TIPS case with an informative video as an attachment. Note: Please refer to this document in the warranty claim and, once diagnosis is completed, select the damage code depending on the component part that is causing the issue. • If the noise stops when the door trim is removed, please proceed in accordance with LI72.10‑P‑067691. Information: In this case, do not use a damage code for the speakers in the warranty claim!

Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic / 9G‑TRONIC automatic transmission) and 725.1 (NAG3 facelift/9G‑TRONIC automatic transmission facelift) For faster, more effective and more targeted diagnosis, Intelligent Predictive Repair (IPR) has been developed and integrated into XENTRY Diagnosis. This ensures an automated diagnosis process. Cause As part of the on‑going quality monitoring process and associated quality and damaged part appraisals, a high number of ineffective repairs have been discovered. Such ineffective repairs have a negative impact on all those involved. For the customer, it means high costs and long repair times and for the dealer, it may result in the warranty claim being rejected. Remedy General note: IPR is available for: NAG3 Classic (automatic transmission 725.0) NAG3 ‑ AMG sports models (AMG 43 and AMG 53 with converter) NAG3 ‑ AMG 63 NAG3 ‑ Hybrid NAG3 Facelift (automatic transmission 725.1) NAG3 facelift (725.1) with engine 139/177 (AMG 43/63) Steps for the Service Advisor: Important: The more information and detail that can be given to the workshop about the complaint, then the more effective the subsequent diagnosis with IPR can be. To this end, a detailed service reception questionnaire has been provided to help the Service Advisor ask the right questions about the complaint. ·Ask precise details about the customer complaint and the conditions and context. ·Fill out the service reception questionnaire (please see WIS document: OF27. 00‑P‑3000‑05A) for customer complaints in detail and forward it to the workshop. Operation steps for the workshop employee: Perform quick test ·Access the transmission control unit via XENTRY Diagnosis ·Select "A customer complaint has been received" and carry out all subsequent operation steps (IPR diagnosis path). ·The IPR repair instructions are displayed. Carry out the IPR repair instructions without performing any further diagnostic or repair steps. ·Important: The IPR repair instructions are binding and must be carried out. Differing repairs are possible; such repairs must be documented in XENTRY in free text. Please observe the information regarding the IPR diagnosis process in XENTRY. ·Conventional diagnosis and subsequent appropriate repairs are only permitted if IPR does not specify any repair instructions. ·Invoicing for the guided IPR steps: Operation item 27‑0640 and 0.1 hours !!!!! Notice regarding warranty: !!!!! ·The use of IPR in association with warranty claims is mandatory! ·If the IPR repair instructions are disregarded without justification, the warranty claims may be rejected and/or are subject to debit. IPR will provide a measure to repair the vehicle based on various data sources (EEPROM, fault codes, etc). Please consider the vehicle maintenance record of the vehicle. For warranty and goodwill repairs, the transmission ECU test log and/or IPR test result must be uploaded into Paperless XENTRY Diagnosis (pXD) . If repair is being determined based of oil pan condition pictures of oil pan MUST be provided to warranty as justification. ·Tamper‑proof documentation: The IPR repair instructions are stored in the control unit log. Please file this document in a tamperproof manner ‑ either in digital form or as a hard‑copy printout and also enclose a printout with the damaged part. In this regard, please comply with the country‑specific warranty requirements of the MPC/general distributor.