*Median odometer reading when the problem happened, where owners gave one. One complaint can name several problem areas.
Unknown or other
vehicle: 2019 Mercedes-Benz GLC 300 Component Involved: Integrated Transmission Control Module (TCM) / Mechatronic Unit Active Diagnostic Code: P073E (Unable to Engage Reverse) Description of Event: While attempting to back out of a driveway, the vehicle experienced a sudden, catastrophic electronic transmission failure. Without any warning or prior symptoms, the vehicle abruptly kicked itself out of gear and dropped into Neutral. The vehicle completely lost all propulsion and ability to move backward or forward, rendering it entirely disabled. This failure occurred directly in the path of oncoming traffic, creating an immediate, life-threatening safety hazard for myself, my passengers, and…
Sep 12, 2026Power train
On April 16, 2026, within minutes of being released from a certified dealership, my 2019 Mercedes-Benz GLC 300 suffered a sudden and total loss of propulsion while traveling at high speed on the Belt Parkway (NY). Despite depressing the accelerator, the vehicle failed to maintain speed and stalled in active traffic. This created an immediate life-safety hazard, forcing me to navigate across multiple lanes without engine power to avoid a high-speed rear-end collision. The vehicle was released to me by Mercedes-Benz of Brooklyn on April 16, 2026, following a repair for which I paid $2,134.94. The dealership diagnosed the issue as a wiring harness/sensor fault and formally certified the…
Apr 16, 2026Visibility › Sun/moon roof assembly
The contact owns a 2019 Mercedes-Benz GLC300. The contact stated that while driving 65 MPH on the interstate, the sunroof suddenly shattered into pieces and flew off the vehicle. The vehicle was driven to a dealer but was not repaired. The manufacturer was notified of the failure. The failure mileage was 106,706.
Apr 5, 2026 · 106,706 milesUnknown or other
I have a MC Benz 300 GLC with $50,000 miles. I was having heating issues so took it to the dealership, which basically advised of the issue describer below, which would cost $14k to repair. Contaminated coolant in Mercedes-Benz GLC 300 models often results from the internal failure of a "desiccant bag" inside the coolant expansion tank, which disintegrates, releasing material that clogs the heater core. Symptoms include black residue in the tank, reduced cabin heat, and engine overheating. Key actions include replacing the expansion tank (reservoir) and flushing the entire system.
Mar 31, 2026Air bags
A message that passenger air bag is damaged/will not deploy appears. Passenger seat belt gets stuck and cannot be opened. Check engine light on-pvc valve issue most likely.
May 1, 2025Unknown or other
SUNROOF EXPLODED AND SHATTERED. I HEARD IT WHILE DRIVING AND HELD ON TIGHTLY TO THE STEERING WHEEL BEFORE I REALIZED WHAT IT WAS. THE DEALER AND MY AUTO INSURANCE HAVE BEEN CALLED, NEITHER PICKED UP, AND I LEFT EACH A VOICE MAIL MESSAGE. NO WARNING LAMPS, MESSAGES OR OTHER SYMPTOMS OF THE PROBLEM OCCURRED.
Feb 27, 2026Unknown or other
My sunroof just exploded while driving on the highway without any impact or warning. It was a clear sunny day. There wasn't a vehicle in front of me. Nothing fell on my windshield nor sunroof. The sudden explosion and shattering of the glass was extremely startling. I had a mesh underneath the sunroof that contained some of the shattered glass so it did not fall on me while I was driving. I'm so thankful there wasn't a car behind me for the glass debris to fall on. Mercedes USA was not helpful, unresponsive for many weeks. They eventually declined repair coverage due to out of warranty, not manufacture defect nor safety issue.
Dec 30, 2025Vehicle speed controlCrash1 injury
I was driving on a street 5mph and all of a sudden my car surged and led me to curb where i knocked hit a steer din and it veered onto someoneâs lawn and hit a huge planter and stopped . Air bags were deployed . I had no control over the car . EDR was preformed and Iâm sure it was a throttle surge issue and cause unintended acceleration . The edr shows I was going 5 miles an hour but then says pedal was pushed to 100%. While traveling at approximately 4â5 mph during a low-speed maneuver, with light accelerator input, the vehicle unexpectedly surged forward. I did not intend to accelerate. The vehicle rapidly increased speed, left the roadway, struck a street sign and a planter, and…
Aug 11, 2025
Owner complaints are submitted to NHTSA by the public and are not verified. Shown as filed (NHTSA removes personal details); long reports are shortened.