Mercedes-Benz C300 won't shift problems

Filed Sep 15, 2026 · Electrical, Engine · CA

The vehicle experienced a severe safety issue involving a sudden loss of motive power in active traffic. 1. Initial Symptoms & Diagnosis: Recently, the Check Engine Light illuminated. Although the light turned off before my scheduled appointment, I still brought the vehicle to an authorized Mercedes-Benz dealership for a safety inspection. 2. Dealer Confirmation: The dealership inspected the vehicle and diagnosed an internal electrical fault with the engine oil control valve and harness. They recommended replacing the parts. Because the vehicle seemed to be running fine and the dealer did not warn me that it was unsafe to drive, I drove the vehicle home to consider the repair. 3. Critical Safety Incident: Shortly after bringing the car home, I was stopped at an intersection. When I attempted to accelerate, the vehicle suddenly entered "limp mode." It lost almost all motive power and would only crawl forward at a very low speed. This sudden loss of acceleration in the middle of traffic put me at an immediate risk of a collision. I had to pull over to the side of the road and restart the engine to regain normal function. 4. Prior Symptom: Looking back, I experienced a similar brief loss of power approximately one year ago. However, the vehicle recovered quickly after I restarted the engine, and no warning lights came on, so I was unaware of the severity of the defect at the time. The vehicle has less than 20,000 miles. An internal engine valve failure causing a sudden loss of acceleration on public roads is a major safety defect. The vehicle is currently parked for safety reasons and is available for inspection upon request.

Filed Aug 16, 2026 · Transmission · CA

Shifting gears when stopped and the car lunged forward while I was stopped at a red light. I almost hit the car in front of me at the red light. Very rough gear changes and changing out of the correct gear to the wrong one and then back into another one. Severe speed changes - jerking the car back or it lunges forward, while driving results in loss of reasonable control of the vehicle and inability to to shift correctly out of traffic. Mercedes benz has a technical service bulletin on this problem and is aware that the 9G-Tronic - internally designated as the 725 transmission (fault code P07B700) is defective and known to experience sudden pressure sensor failures or valve body faults within the transmission control unit which prevents the car from shifting gears corrected or forces limp mode. The repair is a minimum of $5,200. MBZ has known this is a defect and wide spread issue but unwilling to contribute to the repair or recall or respond to my letters and the inquiries of other vehicle owners I have spoken to that have the same issues. It is a catastrophic mechanical failure from a sensor they know is bad and is occurring shortly after warranties are expiring. It is putting all of our lives and the lives of others at risk of an accident due to the failure of their part. Thank you for your consideration.

Filed Dec 22, 2023 · Brakes, Electrical · VA

The ESP®, or Electronic Stability Control system can put the car into limp mode unexpectedly. Say you are driving on route 66 going 50 mph. The ESP system can turn off if a wheel speed sensor or yaw sensor is on the way out. This causes the car to suddenly dramatically brake and limit speed to 5 mph on the highway. Risk of high speed rear end collision and mortality to the driver.

Filed Jul 29, 2022 · Driver assistance, Transmission · KS

Reported to local dealer and corporate office about the issues with shift module not shifting at random, meaning that the vehicle won't shift from park to drive or reverse, and so forth. The local dealer tried to reprogram the software, but the problem still persists. When plugging in my OBD II & DTC readers, code U0103 appairs which translates to "Lost communication with gear shift control module". My concern with this is that I've had this issue while in traffic, which would make my vehicle a hazard. When it comes to the collision prevention system, the system randomly turns on and off, meaning that when it's needed it might turn on, but when it's not needed it randomly turns on. Once again, addressed this with a local dealer and Mercedes Benz corporate with no avail. My concerns here is that the vehicle could prematurely brake causing an accident or not brake at all causing an accident.

Filed Feb 21, 2021 · Acceleration, Driver assistance · 91,000 miles · WI

On february 9th, during my morning commute on the interstate the car lost power to the drivetrain. Message that displays was "collision assist plus inoperative" along with cruise control inoperative. With an amber esp light illuminated, there was no engine light on. When this message appeared the car would no longer accelerate (limp mode). In avoidance to being in a rear end collision I quickly pulled over, turned off the car and turned back on. Inoperative message, limp mode and esp light was cleared. I called dealer to notify. My thought was the battery is a dud (was replaced the day prior), the car needs a software reboot due to the new battery or car was not connected to the "memory saver" correctly. Or the sensors were dirty. So I did the easiest. I washed the car. This problem continued to happen 5-6 times more over the next few days stalling on the freeway at 65-75 MPH. Extremely dangerous & life threatening. No engine problems apparent. Seems to be radar or software. This is extremely dangerous while on the highway, I found many other with this same issue on the federal safety agency. I attached a picture of car showing message with no power. My seatbelt was off as I was on side of road trying to get to gas station. This issue is cleared by turning car on / off. Then it happens again hours or a day later, loss of power at highway speeds. Coast over.

Filed Dec 5, 2019 · Steering · 105,394 miles · NJ

On or about 11/24/19, vehicle was parked in front of the house overnight and next morning, the vehicle did not start due to steering being locked electronically. Car did not have any power besides doors opening and would not shift into neutral. The vehicle was towed to a local dealer and service advisor contacted me to inform me that the vehicle locked the seething due to faulty switch. Vehicle was repaired and return to me on 12/4/2019. At this time, I am concerned for my safety due to possibility that the steering might lock while the vehicle is in motion.

Filed Dec 15, 2016 · Airbags, Electrical · 135,000 miles · TX

My 2010 mercedes c300 has a faulty electronic steering lock fail-which left me stranded sitting in the park lot about 30 minutes from home. Car would not start I tried to start my car and nothing happens. When I turn the key to on nothing lights up, no crank, no clicks, no windows and no radio. I would lock and unlock with the remote but that was about it. I tried jumping and I tried both keys still nothing happens when I turned the key. Steering wheel was locked and gear stuck in park. Had to have it towed to the mb dealership to have the steering lock and key replaced and ending costing $1,124.00. I have read that this has happened to a whole of mb's and should be a recall. I mean really we pay to have a quality car and so far my mb has had a stinky AC that mb could never figure out how fix, taillight recall, found oil leaking from oil centerfuge cover that cost $199.62 but yet it still leaks oil., currently waiting for the takata airbag inflator recall from april 2016 and today is dec. 2016. Very disappointed in mercedes and will not be purchase again nor will I recommend to anyone. Even the service at the dealership has gone down. Quality and customer service is not what it use to be.

Filed May 13, 2016 · Acceleration, Electrical · 12,295 miles · NC

Was driving on city street, and the collision prevention assist disabled warning sign came on and I lost power to the car. I'm told this is called "limp mode." I tried to pick up speed by pressing throttle to the floor, but got no reaction at all. Then some power came back, but not much. Each time I braked to stop for light or turn this would happen. After I got home I restarted the engine and it seemed normal again. However I was afraid to drive it, especially since in the last six months my power steering also failed, and had it towed to dealer. They ran tests and no code for failure was found. They said they found some software updates which they did. Unfortunately, after I picked up the car from service I saw that my main complaint wasn't even mentioned. Only that I sometimes had problem with collision control warning going off for no apparent reason.

Filed Feb 25, 2016 · Transmission · 50,000 miles · MN

Gear shifter will get stuck in park when parked on a slight incline, such as a driveway or small hill. I absolutely have to park on a flat surface if I want to get my shifter out of park. I have to tap on the top of the shifter and continue to try to get it out of park. This can take anywhere from 10-30 minutes and has happened multiple times. Very frustrating and I've only had the car a couple of months. Now I have to put money in to fix it already. Why is there not a recall on these vehicles with this problem? From my research, it seems as though plenty of mercedes has this problem.

Filed Oct 12, 2015 · Steering · 84,000 miles · TX

I went to the park with my wife and 1 year old son, I parked the car and returned a few hours later, the steering column was locked and the key would not start or unlock the steering wheel, the car had to be dragged out of parking space since the steering wheel would not unlock and the car was stuck in park. It was towed to the dealership where they diagnosed a bad steering column $1600 repair bill, after researching the issue I have found hundreds of owners of the same vehicle which have the exact same issue and repair, so this is a very common and know issue by mercedes benz. I believe that if the steering column can become locked it could potentially turn very dangerous if the car is in motion because the operator would be unable to maneuver the vehicle.