2015 Mercedes-Benz C300: sudden loss of power

Filed Mar 31, 2023 · Engine · MD

My vehicle is a 2015 C300 AWD. One day I was driving on the highway and noticed white smoke coming out of the exhaust. The check engine light came on shortly after as I pulled over. Being that I was less than a mile from my house, I decided to go park the vehicle. I noticed that it was losing power and had problems going above 45mph. Since my vehicle had 99k miles. I took it to my indy mechanic that has worked on the vehicle since it has been out of warranty. When he diagnosed the vehicle, 48 codes came up. He suggested we change the spark plugs and coils, which we did. Didn't fix the problem. Then he suggested we change fuel injector 1, which we did. That didn't solve the problem. I decided to take it to the local Mercedes dealership where they did another diagnostic test. And like many others here, cracked piston/cylinder 1 dead. I'm looking at $18,000 in repairs. I told them no thank you. The car is now sitting in my garage. I really hope Mercedes makes this right with its customers. There is no reason why this many people should be having this exact same problem. Vehicle Symptoms: White smoke out of exhaust Check engine light on Cylinder 1 Misfire Burning Oil Causing loss of power Radio randomly shuts off & went into Anti Theft Mode

Filed Mar 27, 2023 · Engine · CA

my car is a 2015 C300 class Mercedes-Benz, as I was driving, the car suddenly and without warning began to vibrate and shake violently and immediately lost power. Fortunately I was off the freeway, a serious accident could have resulted. I took it to the the local MB dealership and they told me that the car failed a compression test in the #1 cylinder and that the engine would have to be replaced at almost $17000. Of course, this was beyond warranty, Mercedes know it’s a defective product, they refused to act responsibly. This cracked piston which is a design flaw by Mercedes needs to be recalled, a lot of people are reporting the same issue.

Filed Jan 12, 2023 · Engine · VA

Vehicle experienced loss of power and rough running when check engine light came on. Mercedes dealer reported one of the pistons cracked resulting in catastrophic engine failure with just shy of 61,880 miles on it.

Filed Jan 6, 2023 · Engine · PA

These cars have a known wrist pin failure, mercedes refuses to cover the cost of repairs as its not a recall. My vehicle is the specific model and year this is known for, and my car is making these piston slapping sounds, worse everyday. Worse on deceleration, goes away when warmed up, just like the reports. I am afraid I'll lose power while driving and hurt myself or others.

Filed May 16, 2022 · Engine · CA

Cracked cylinder #1. Causes rough idle, loss of power and lots of white smoke out the tail pipe. This is dangerous for anyone behind the car trying to see through the smoke then loosing power and other vehicles almost hitting me. Mercedes know they are defective but because of the large cost associated with repairing them they will not fix.

Filed Apr 15, 2022 · Engine · CA

Cylinder #1 losing compression. Onset acute after exiting freeway. Car lost power. Engine warning light turned on. Independent repair shop advised compression problem in Cylinder #1. Dealer then inspected and advised there was compression loss in Cylinder #1. Dealer recommended engine replacement (not repair). The car only has around 46,000 miles and is a 2015 model.

Filed Mar 4, 2022 · Engine · CA

Long story short, I own a 2015 C300 Mercedes with 59,500 miles I was driving on the street when my engine started shaking so rough and my car lost power. I panicked and pulled over and drove 10mph all the way home. My vehicle would shake rough, couldn’t exceed 10mph and would make loud noises. I take it to the Keyes Mercedes dealership and they tell me it’s a cracked piston. I couldn’t believe it because I only have 59k miles. I have my vehicle records so I have been up to date on my maintenance. They dissembled my engine and couldn’t find the cause to the failure but found the cracked piston in cylinder #1 and damage to the cylinder walls. They recommended to replace complete engine and it will cost me about more than $18,000!! The piston falls under Mercedes 7 year/70k miles emissions warranty and yet they deny coverage. After doing lots of research I come to find out that I’m not the only victim that has suffered the exact damage. People that also own a Mercedes c300 and other models are now without a vehicle and looking at a repair of $18k+ and making a car payment for nothing. This has caused us stress, inconvenience, and damage to our mental health. Keyes Mercedes located in Van Nuys is also aware of the common cracked piston issues on their vehicles. In 2 days I mark 4 months without my car. Please help!!

Filed Jun 28, 2021 · Engine · 66,000 miles · CA

I was in middle line on I-5 SB San Diego doing 40-60MPH when my car suddenly started to shudder, shake and smoke came from the exhaust. The car lost power and the check-engine light came on right away. I was told that Cylinder 3 lost pressure, that the engine wall was damaged and that possibly the piston and wrist pin are cracked. My car has only 66K miles and the Mercedes Benz dealership is telling me that I need a new engine that will cost $19,000. After doing some research I have found out that I wasn't the only one with this issue. I have listed an example here: "HERE IS A MAJOR ISSUE WITH THE 2015 M274 MERCEDES ENGINE REGARDING THE WRIST PINS. MERCEDES HAS ISSUED NUMEROUS INTERNAL SERVICE BULLETINS ABOUT THE ISSUE. THE ENGINES WERE MANUFACTURED WITH WRIST PINS WITH TOO MUCH TOLERANCE THAT SLAP AGAINST THE PISTON WHEN OPERATING THAT COULD LEAD TO PREMATURE ENGINE FAILURES. THERE ARE HUNDREDS OF COMPLAINTS ON ONLINE FORUMS OF PREMATURE ENGINE FAILURES (PRE 100K MILES)." MBUSA requested from me proof that the car was serviced on time and with the correct parts. Once I was able to prove everything they told me that they were sorry but I still need to pay for everything. They did offer a "10% good-will discount". I wish they told me when I was buying a car that after every 6th oil change I will need a new engine. PLEASE MAKE MERCEDES MAKE THIS RIGHT AND FIX THE AFFECTED CARS THE RIGHT WAY.

Filed Feb 22, 2021 · Body · 71,000 miles · WI

Upon submitting a claim for my "inoperative" sensor issue and the car losing all power at highway speeds. I discovered your claim about panoramic sunroof detachments. Well you are in luck as I have a lovely mercedes with a roof panel that I had to glue to the track as it came apart. The hinge on right side is loose. I can no longer open the sunroof or it will catch wind as if it's about to dethatch. Driving the sunroof is so loose that it will not close without the help of holding it down so it locks into place. Brought it into the dealer last summer and they brushed it off and tried to charge me over $2,000 to get it fixed. They said "common issue" I would produce pictures, however my car is currently sitting at a mercedes factory shop getting its other safety issues taken care of.

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 Mar 9, 2018 · 13,400 miles · WA

Collision assist inoperative dash light came on while highway driving followed by a loss of power and acceleration. Vehicle needed to be turned off and restarted to be drivable.

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.