2021 Mercedes-Benz GLC 300: stuck in gear or won't shift

Filed Aug 30, 2026 · Engine, Fuel system · CA

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.

Filed Nov 12, 2025 · Engine · VA

There is a hesitation in or "shuddering" that causes the car to go into limp mode while in operation. I was in traffic and the car just powered down and would not get up to and or maintain speed. I contacted the local dealership and was told that there are other models and or engines in this car that have this issue and that they actually have a recall on this issue. The dealership noted that they have 1 or more that require this exact repair on every single week. The dealer told me what was wrong with it by the code it threw... He didn't have any hesitation because he is so familiar with this issue. The warning lights came on after the car powered decreased... there was no "pre" warning that this was going to happen.

Filed Oct 24, 2025 · Engine · AZ

Car has experienced rough idling, sluggish to no acceleration, check engine light illuminates and no shifting of gears regardless of speed. It appears to be going into limp mode. This has occurred monthly for the last four months. After pulling over, the car is turned off, wait five seconds and then turn it back on the car operates like nothing has happened. Here is when it has happened: 1.In a drive-thru lane to get some food 2.Waiting in a left-hand turn land 3.Driving through a parking lot at 10 mph 4.Driving on a road at 45 mph The date below is the last occurrence.

Filed Mar 22, 2025 · Engine · OK

On [XXX] my GLC 300 AWD while driving back from work started shaking, went into limp mode, engine started misfiring and check engine light came on. Pulled over into a parking and called Mercedes-Benz road side assistance, they sent a tow truck and the car was towed to the Mercedes-Benz of Oklahoma City. The service department informed us of cylinder head failure and told SUV needs cylinder head replacement that would be covered under the extended Mercedes warranty. As of March 22, 2025 SUV is still at the Mercedes dealer and not fixed. This is the second time in past few months GLC went into limp mode and lost power and acceleration while on road, it was towed to the Mercedes dealer. They initially said they couldn't find anything wrong but later performed an update of engine management software on the recommendation of Mercedes-Benz USA. Car was fixed at that time. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 27, 2022 · Electrical, Fuel system · KY

My car was bought new in October 2021 & I began having problems after having it for 6 months & the mileage at that time was about 4000 miles - it was in April 2022 & the check engine light came on & I had a loss of power to where it slowed down & would not go any faster than about 30/35 miles an hour going on a straight road way & no faster than about 10 miles an hour going uphill. The engine sounded funny as well. It had to be towed to the dealership for repair. This incident happened again a month later & it was towed to the dealership at that time. The next incident just happened this month (mileage=6620) & again it was towed to the dealership for repair. Same scenarios all 3 times. This last incident, I was told that it is glitch & they don't really know what is causing my car to basically go into "limp mode"; however, they are awaiting a software update that they expect will resolve the problem, but they are not sure when it will be available for installation & did not give me a timeline. In the meantime, I was given back my car as I was the 2 other times without a resolution or security that my car is doing to make it to & from my destination. The car is still under warranty & just under a year old now. I was told by the dealership that they have no other customers complaining of this problem & they feel it is very isolated. I asked them to reach out to their corporate office in hopes of making a deal with me as I have lost all confidence in the car, but they reported having no luck in reaching anyone to discuss my problem. The 3 incidents where the car had to be towed were very scary for me as other cars were blowing their horns at me because I could not accelerate & go any faster & when I was going up a hill - it was really bad. I was very lucky that all 3 times happened not far from my home & not on the interstate as the outcome could have been very bad for me in regards to my safety.