*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Electrical system
Moisture began collecting inside the left headlight assembly, even though the housing should be sealed. Over time, the condensation increased and the front left turn signal failed. The vehicle displayed warning messages for the turn signal, low beams, Blind Spot Assist, Traffic Sign Assist, and Active Brake Assist. The failed turn signal reduces the vehicle's visibility to other drivers and creates a potential safety hazard. A similar moisture intrusion issue was the subject of NHTSA Recall 22V-261 for certain 2021 Mercedes-Benz GLC vehicles, but this vehicle was not included in that recall despite exhibiting the same symptoms. The vehicle is available for inspection.
Jul 21, 2026Power train
The engine-driven vacuum pump and turbocharger boost-control vacuum system malfunctioned. The vehicle developed insufficient vacuum to the boost-control system, resulting in a P0299 turbocharger underboost fault and reduced engine power. The vehicle is available for inspection upon request. The vehicle experienced a noticeable loss of peak power and reduced acceleration. Although it did not enter limp mode, unexpected reduced acceleration could create a safety risk while merging onto a highway, passing another vehicle, entering or crossing traffic, or attempting to avoid a collision. An authorized Mercedes-Benz dealership scanned the vehicle, confirmed fault code P0299, and documented that…
Jun 10, 2026Engine
At just 30,000 miles â less than half the mileage at which these failures are typically reported â my GLC 43 was found to have active oil leaks in multiple locations: 1. Front engine covers â oil is seeping from both the front cover gasket area and migrating downward along the engine block. The dealer recommends a full reseal of the front covers at a quoted cost of $1,944. 2. Radial shaft sealing ring of the front axle gear â is actively seeping gear oil, with a quoted repair cost of $1,718. My concern is not limited to cost. Oil migrating from the front cover area toward the lower engine, accessory belt, and turbocharger assembly creates a documented fire risk. The turbocharged…
Apr 6, 2026Exterior lighting
2021 Mercedes GLC 43 headlight is inoperable. Same as reported in campaign 22V261000: "Headlight failure can decrease visibility for both the driver and surrounding traffic, increasing the risk of a crash." Although our car was produced before the dates reported in campaign 22V261000, I believe this is the same defect and the recall should apply to all MY 2021 cars as this is a serious safety issue. The dealer will not repair under warranty.
Sep 25, 2025Unknown or other
Panoramic sunroof exploded while driving.
May 8, 2023Tires
The contact owns a 2021 Mercedes-Benz GLC43 equipped with Continental Tires, Tire Line: Sport Contact, Tire Size: 255/40/ZR21, DOT Number: AFHDD76M. The contact stated that on several occasions while driving at approximately 30 MPH and at low speeds on wet pavement, the vehicle started to shake, and a loud abnormal noise was heard in all four tires. No warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the tires needed to be replaced; however, tires were not replaced. The manufacturer was notified of the failure and the contact was advised to call the NHTSA Hotline. The failure mileage was approximately 10,000.
Mar 31, 2022 · 10,000 miles
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.