2018 Mercedes-Benz GLC 300 Driver assistance Problems

While pulling into a parking spot with my foot hovering above/on the break, the car lurched forward as if someone had floored the gas pedal. As my foot was already on the break, I slammed down onto the break and the car came to a stop, several feet ahead of the top of the parking spot, and into the woods. I called roadside assistance for the vehicle to be towed to the dealership for repair, as I did not find it safe to drive it. The dealership was unable to replicate the issue, but they told me that due to the severity of the issue, they weren't supposed to check it themselves. Instead, I needed to report a case to Mercedes Corporate and the communication from here would be handled directly between corporate and myself. It's been over three weeks since this occurred, and I have not received communication that the car has been tested further, or any next steps. The car is at the dealership. It's also important to note that this same issue also happened months before, while backing out of a parking spot in reverse. I didn't report it because it was a confusing thing to happen and I couldn't believe a car would gas on it's own. When it happened a second time, I knew it was a problem. This was not a case of user error or the floor mat being in a wrong position. What component or system failed or malfunctioned, and is it available for inspection upon request? Speed control / yes How was your safety or the safety of others put at risk? The car spontaneously accelerated and could have caused harm if people or structures were in its path. Has the problem been reproduced or confirmed by a dealer or independent service center? Has not been reproduced Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? Not that I know of Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear? No

NHTSA ID

11687525

Incident

Aug 23, 2025

The car does not go into drive from reverse and will sometime automatically shift itself from a low drive gear (D1) into Neutral without warning. After this happens - the car also can't get back into D1. It takes about 20 seconds for the car to shift back into a Drive gear and it will jolt into D3 violently. This has been a scary experience on many occassions - especially at red lights when this happens and we can't get the car out of neutral for some time. This was diagnosed by mercedes dealership near us as a fawlty sensor in the transmission. It is extremely expensive to fix and is specific to mercedes meaning it has to be done by a MB dealership. We applied for good will for assistance but were denied. The car has been maintained very well - this is not a maintenance issue but a specific sensor failure of a mercedes sensor in the transmission. We are thankful no one was hurt - we had our 8 year old daughter in the car when stalling out several times at red lights and it's been a very scary situation.

NHTSA ID

11676731

Incident

May 15, 2025

when the car is in drive it will stop like it is in park unable to drive or put in reverse. This happens at random times on the road. The car will then skip gears and go into Neutral then skip an again on its own and go into drive.

NHTSA ID

11592323

Incident

May 8, 2024

The windshield washer pump failed due to the Sam unit. Failing I was in the mountains, started my car the windshield wiper malfunction light came on the wipers worked for a minute, so I turned them off, drove over the pass and tried to use my wipers, and they did not work. The back wipers did work. I took my car to my mechanic in Cheyenne, who discovered that’s the SAM unit Ruined the windshield washer pump. No one else has inspected it other than my mechanic. I have learned that there are others complaining of the same issue online. This is a dangerous issue when you are driving in a storm with no windshield wipers. My mechanic believes this should be a recall issue, and so do I. The Mercedes dealership said my mechanic, a faulty Sam unit to replace the Sam unit that went out. Now my car is throwing all kinds of codes and the back windshield wipers do not work.

NHTSA ID

11577478

Incident

Feb 15, 2024

I m having issue with te code po52e its annoying i fixed and still the same issue

NHTSA ID

11555853

Incident

Nov 18, 2023

Vehicle stopped while driving on road. Car show "active brake assist malfunction" on the dashboard, immediately following the car will not accelerate. Shut the car off and restart, then the "check engine light" comes up. The active brake assist does not come up again, but the check engine light states on. I have taken the vehicle 5 times for this issue to the dealer, car is currently at the dealer. Reason of my report, is that I consider this situation extremely dangerous and should be investigated further. [XXX] INFORMATION Redacted PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6).

NHTSA ID

11525173

Incident

Mar 8, 2023

I was driving when engine light came on.It then went into limp mode.The car would not accelerate we me trying to cross a busy 60mph road.I was almost killed.The code after it was tested p2138 .Pedal position sensor.This fault almost killed me....

NHTSA ID

11513104

Incident

Mar 15, 2023

WHEN I WAS PULLING INTO A PARKING SPOT AT A LOW SPEED, THE CAR ACCELERATED AND LURCHED FORWARD, HITTING A WALL, WHICH DEPLOYED THE AIRBAGS. WHEN THE CAR STARTED TO ACCELERATE, I HIT THE BRAKES BUT THEY DID NOT ENGAGE.

NHTSA ID

11349114

Incident

Aug 1, 2020

Mileage

21,000 mi

'THE FIRST INCIDENT - OCCURRED IN AUGUST WHEN I STOPPED AT A STOP-LIGHT. I STARTED DRIVING WHEN THE LIGHT TURNED GREEN AND THE CAR WAS ACCELERATING AS NORMAL. THERE WERE CARS BEHIND ME ACCELERATING AS WELL AS NORMAL. MY SUV AUTOMATICALLY SHIFTED FROM DRIVE TO NEUTRAL BY ITSELF AS I CONTINUE TO ACCELERATE TO MOVE WITH THE NORMAL FLOW OF TRAFFIC. THE VEHICLE AUTOMATICALLY SLOWED DOWN TO NEUTRAL '2ND INCIDENT - THE SAME ISSUE OCCURRED AGAIN WITHIN TWO WEEKS I WAS DRIVING ON THE LONG ISLAND EXPRESSWAY AT APPROXIMATELY 40 MILES PER HOUR IN HEAVY TRAFFIC WHICH HAD COMMERCIAL TRUCKS. THE VEHICLE AUTOMATICALLY SHIFTED FROM DRIVE TO NEUTRAL ON ITS OWN. THIS NEARLY CAUSED A PILE UP ON THE LIE WITH THE CAR IMMEDIATELY BEHIND ME RUNNING INTO THE BACK OF MY CAR. '3RD INCIDENT - I STOPPED AT A STOP SIGN WAITING FOR THE LIGHT TO TURN GREEN IN ORDER TO MAKE A RIGHT TURN. I MADE A RIGHT ON VERY BUSY STREET AND THE CAR STARTED SHUTTING DOWN AND DECELERATING INSTEAD OF ACCELERATING. I URGENTLY STEERED THE CAR OVER TO THE SIDE OF THE ROAD AND TURNED IT OFF. I WAITED FOR A FEW MINUTES AND RESTARTED THE CAR AND IT SEEM TO HAVE BEEN WORKING. '4TH INCIDENT - ON SUNDAY SEPTEMBER 18TH, THE VEHICLE COULD NOT START SO I HAD TO CALL MERCEDES BENZ ROADSIDE ASSISTANCE. THE ENGINE DIDN'T MAKE ANY ATTEMPT TO START. THE LIGHTS DIDN'T TURN ON. THERE WAS ABSOLUTELY NO RESPONSE TO A KEYLESS OR MANUAL START. 'SEPTEMBER 29TH ' I PICKED UP THE SUV AND IT DROVE WELL WITHOUT ANY INCIDENTS 'OCTOBER 1ST ' THE VEHICLE AUTOMATICALLY SHIFTED FROM DROVE TO NEUTRAL AFTER MAKING A RIGHT TURN ON A VERY BUSY STREET WHICH NEARLY CAUSED AN ACCIDENT WITH ANOTHER CAR HITTING ME IN THE REAR. THIS NEARLY CAUSED A 'PILE UP' BECAUSE OTHER CARS WHERE URGENTLY SLAMMING THEIR BREAKS BEHIND ME TO PREVENT FROM HITTING THE CAR IN FRONT OF THEM. I WAS DROPPING MY SON OFF TO SCHOOL AND HE WAS SITTING IN THE BACK SEAT.

NHTSA ID

11140717

Incident

Oct 1, 2018

Mileage

6,000 mi