Owner-reported issues — NHTSA
268 complaints filed with the National Highway Traffic Safety Administration for the C166 across model years 2012–2015. Federal public records, updated weekly.
| ENGINE | 45 reports |
| ELECTRICAL SYSTEM | 36 reports |
| UNKNOWN OR OTHER | 24 reports |
| FUEL SYSTEM | 24 reports |
| FUEL/PROPULSION SYSTEM | 22 reports |
| LANE DEPARTURE | 13 reports |
| GASOLINE | 13 reports |
| STEERING | 12 reports |
Selected owner reports
2012 · STEERING
The contact owns a 2012 Mercedes-Benz ML350. While the contact’s wife was driving approximately 30 - 35 MPH, the message "Do Not Drive Vehicle" was suddenly displayed. The vehicle was taken to a mechanic, and the brake fluid reservoir was topped off. The mechanic was unable to find any leaks. The vehicle was not diagnosed or repaired. The message turned off and was displayed again 4 hours later. The contact was called by his wife, and the vehicle was driven to the residence after the brake fluid reservoir was refilled. The contact stated that a half mile later, the message was displayed again.
2012 · FUEL/PROPULSION SYSTEM
ENGINE STALLED DRIVING ON INTERSTATE HIGHWAY AT 70mph. MECHANIC DIAGNOSTIC INDICATED TO BE FAULTY FUEL PUMP and/or FUEL PUMP CONTROL UNIT. THIS ISSUE HAS BEEN RECOGNIZED BY MERCEDES BENZ AS A FAULTY ISSUE AND SUBJECT TO RECALL. UPON CALLING MERCEDES BENZ DEALER WAS TOLD THERE WAS NO RECALL ON THIS MATTER FOR MY VEHICLE CONTRADICTING THIS ISSUE PREVIOUSLY RECOGNIZED BY MERCEDES BENZ.
2012 · ELECTRICAL SYSTEM
My name is [XXX] My vehicle cut off on me 3 times twice while stationary and once at an intersection. Found oil in engine control module due to failed cam position sensors. Oil has traveled through the engine harness to ECM causing oil to get into module and cause it to shut down but it did start back up. This is very dangerous and could cause serious injury to someone. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
2012 · SEAT BELTS
The driver's seat belt is locked and the retractor is not working without any reason. The front adaptive cruise control radar is also not working, along with the crucial blind spot sensor. Because of this, the vehicle cruise control (even without adaptive mode) is not working at all. This is a big safety issue and it is illegal to even drive this car without the seat belt working.
2012 · ENGINE
The contact owns a 2012 Mercedes-Benz ML350. The contact stated while driving uphill at an undisclosed speed, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. In addition, the contact stated that the vehicle was shaking abnormally. The contact stated that the abnormal shaking occurred at various speeds. The vehicle was taken to the dealer where it was diagnosed with timing chain failure. The contact was informed that the timing chain needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure but provided no ass
2012 · STEERING
Turn signals will not operate, dealership quoted me $1400 3 years ago, had the work performed and now the issue is happening again and I am being quoted the same amount of money. This is a safety concern if I cannot signal to others where I am turning!!!!! This could cause an accident!!!!! This is highly unsafe!!! What if my kids were in the car?! Talking to customers in waiting lounge at dealership other people have had same issue!! The one time they stopped working I had a person hit me going 30 mph, could have been much much worse.
2012 · EXTERIOR LIGHTING
My indicators stopped working a month prior to accident, then they started working again. On March 10th the issue happened again where I turned my signal on and no light appeared and no light on the dash with the indicator sound either. Boom, I had sideswipe someone on a major road causing an accident. NHTSA needs to do something about this because corporate won’t do anything!
2012 · STEERING
Steering column module is intermittently not working as intended, therefore the blinkers will sometimes not work causing it to be a safety concern if I can not signal where I am going. When looking this issue up online I have seen numerous different forums and posts where people have had the same issue. When I took my vehicle to the dealership they had told me that this is very common with the vehicle I have and they do the fix all of the time, just for the issue to happen yet again later down the road.
2012 · FUEL SYSTEM
The contact owns a 2012 Mercedes-Benz ML350. The contact stated that while her husband was driving at an undisclosed speed, the vehicle made an abnormally loud sound and then stalled. Additionally, the vehicle failed to accelerate properly while driving. The contact's husband coasted the vehicle to the side of the road. The vehicle was restarted and driven to the residence. The vehicle was taken to an independent mechanic, who diagnosed that the fuel pump needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure. The failure mileage was approximately 7
2012 · STRUCTURE
I have own this vehicle on July 2023. I have recently noticed the exterior paint is peeling off quickly all over the body.
2012 · FUEL/PROPULSION SYSTEM
While driving, vehicle stalled. Mechanic found water in spare wheel Well. And fuel module and fuel pump shorted out. Had vehicle repaired; 07/22. The vehicle stalled again in 12/22. Mechanic found water in spare wheel well. Had to replace fuel pump. In February,2023, Mercedes Benz notified me of a recall, NHTSA Recall I D: 22V955 ; water intrusion in the spare wheel well. And, stated their local dealer would repair vehicle or reimburse me for the cost of repair, if I had the repair done already. I submitted receipts and documents pertaining to the repair. The Mercedes Benz Dealership refused
2012 · EXTERIOR LIGHTING
When reversing the vehicle the brake pedal jumps with your feet on the brake pedal and a nose rattles,when driving and you have a sudden stop motion the vehicle brakes pedal with your feet on it it’s very hard to push the brake Pedal . Reversing the vehicle very strong nose and the vehicle doesn’t stop right away
Source: NHTSA consumer complaint database · synced 2026-09-21