2015 MERCEDES-BENZ C300 Complaints

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while his wife was driving at an undisclosed speed, the roof panel detached from the vehicle and fractured. The contact stated that the roof panel had previously been replaced, but the failure occurred. The vehicle was taken to the dealer, where it was determined that the front roof panel needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 23V854000 (Structure); however, the VIN was not included in the recall. The manufacturer was made aware of the failure. The failure mileage was approximately 70,000.

Check Engine light came on recently, fault code P052E is identified by scanner. Car has 60,000 miles on original it. MB dealer wants to charge $300 for diagnostics, repair job (parts and labor) may cost over $2,000. Since this is critical emission compliance part/system, why is it not recalling?

Panoramic glass sliding plastic brackets broke off while driving at 25-35 mph Lifting up the glass off the vehicle. Quick reaction saved the large detached glass from flying off into the roadway injuring or killing someone. Vehicle was 5 years old and out of warranty. Dealer estimated repair cost at $2500

On May 27th, 2025, during highway driving suddenly the sunroof got open by itself for like 3 inches upwards from the front and after exiting the highway i stopped and push the sunroof downwards by applying the force and apply duct tape all around the sunroof to keep it protect from sun and rain so i am not driving anymore before getting it resolved.

Rear-subframe corrosion at the lower-control-arm mounts has progressed to the point where both arms have play and produce loud metallic bangs while braking or turning at low speed. Two independent shops lifted the car, documented flaking rust around the bushing sleeves, and advised the subframe is structurally compromised and could let a control arm detach under load. The corroded subframe remains installed and can be inspected on request. Safety risk: a detached rear control arm would cause sudden, unpredictable steering and loss of control. The vehicle already pulls right under braking, and feels very unstable in curves Problem has been reproduced and photographed by two independent repair facilities. No manufacturer representative has inspected the vehicle so far. Additional component failures possibly linked to the same progressive chassis stress: premature wear of both front CV axles; timing-chain stretch with worn guides; slack oil-pump chain; upper & lower oil-pan gasket leaks; water-pump seepage; right engine-mount collapse; persistent misfire traced to a loose intake-hose clamp; transmission-cooler hose clip released under pressure, dumping all ATF and destroying the automatic transmission; excessive play in all four lower control-arm bushings. The transmission and the other components were replaced 1-2 months before the subframe bro History: A faint clank from the rear suspension first appeared roughly three years into ownership. Dealer service dismissed it as “normal noise,” and warranty would not cover “loud clanks,” so the issue went unaddressed. The noise has grown steadily into the current condition, suggesting long-term subframe corrosion that was never inspected or remediated. No collision, flood, or off-road use; the car has typical Northeast winter-salt exposure. The failure pattern matches subframe-corrosion cases already acknowledged by the manufacturer on this model, although this serial number is not yet included in the official campaign.

Power steering malfunction Car unable to drive I believe there is supposed to be a recall for this issue but not popping up when I put in VIN number Warning lamps come up. Sometimes every light on dashboard. Took it to Mercedes but it was when code was not popping up and they said I needed a new battery. Did that but still an issue. Has also happened when driving. Sometimes collision assist plus light comes on and power steering acts up. Light I am pointing at in picture is another light that consistently pops up I have been able to intermittently fix problem by resetting computer by unplugging battery for 15min or longer. As well as confirming full service on vehicle. Now it isn’t working though.

The contact owns a 2015 Mercedes-Benz C300. The contact stated that while driving at an undisclosed speed, there was an abnormal clunking sound coming from the front suspension of the vehicle. No warning lights were illuminated. The vehicle was taken to an independent mechanic, who diagnosed a failure with the steering rack locknuts, observing that the steering rack had become loosened. The vehicle was not repaired. The vehicle was then towed to the dealer, who confirmed the diagnostic result. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 18V850000 (Steering), but the VIN was not included. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA hotline for assistance. The failure mileage was 70,000.

I took the car for annual maintenance to Mercedes-Benz dealership. After routine check up they came back to report rusty rear subframe and told me that needs to be replaced. However this part is really expensive and models from 2008 to 2015 C300 had the same issue(premature rust) and they all received extended warranty from Mercedes-Benz for free replacement. I wanted to report this safety issue for C300 model including mine that is not covered under extended warranty.

Rear subframe broke while driving- made stearing/controlling/breaking car very difficult & dangerous.... After reviewing on internet- MB is aware of this problem

Sunshade on panoramic sunroof broke off and tore sunshade. Took it to MB service center and was told it is known issue for that model and many more with some part snapping off causing the damage and cost to repair is between 2500-3000. Have been reading online and lot of people seem to have same issue with the panoramic sunroof and shade not syncing together. Seems to be concern manufacturer should be looking at if there’s numerous vehicle with same issues. Part snapped off when trying to open up sunroof on hot summer day