Mercedes-Benz ML350 won't start problems

Filed May 22, 2026 · Fuel system · NH

The failed/malfunctioning component appears to be the fuel pump controller / fuel pump control unit, and possibly the fuel pump system. The Mercedes-Benz dealer identified water/moisture-related damage and corrosion at the fuel pump controller area. The failed component should be available for inspection if the dealer preserves the part during repair. I have requested that the dealer not discard the damaged component. My safety and the safety of others were put at risk because the fuel pump controller is related to fuel delivery. If it fails, the vehicle may not start, may lose fuel supply, or may stall while driving. This creates a safety risk, especially if the vehicle stalls in traffic, at an intersection, on a highway, or during normal driving. The problem has been confirmed by a Mercedes-Benz dealership. The dealership diagnosed water/moisture damage to the fuel pump controller area and provided an estimate of $768.22 for fuel pump controller replacement, plus $244.88 for the inspection fee. The dealer also indicated that this was the first inspection and that the fuel pump itself may also need further inspection or may have related damage. The vehicle/component has been inspected by a Mercedes-Benz dealership. Mercedes-Benz USA / the manufacturer’s representative has also reviewed the case through its goodwill process, but they refused to treat it as recall-related coverage. To my knowledge, the vehicle has not been inspected by police or insurance representatives. Prior to the current failure, the vehicle had starting/no-start related symptoms beginning around the middle of 2023. The engine could not start successfully at times. I do not recall receiving a clear warning lamp or message specifically identifying the fuel pump controller before the failure. However, the symptoms were consistent with a fuel delivery problem, and the dealer later confirmed water/moisture corrosion damage in the fuel pump controller area.

Filed Nov 20, 2025 · Fuel system · CA

As we were driving 50mph, the car stalled and lost all power. The dashboard lights all lit up and the car wouldn't start. I don't get unnerved easily and it was fairly intense not being able to move your car out of traffic. After about 5 mins, the car would start again only to stop a minute or so later. After taking the car to the dealer, the issue stemmed from the fuel pump electronics board getting wet in the spare tire wheel well where water was accumulating. This was part of the recall and the dealer installed a drain and replaced the board. HOWEVER, this issue again happened nearly one year later in our next rainy season. After taking it to the dealer, they said WE would need to replace the electronics board ourselves. We asked about the recall and they said they fixed the issue by installing the drain plug and there was nothing else they could do for us. Even the service adjuster was upset and very sympathetic to our plight as the car was obviously not fixed. Even though the drain plug was installed, the water was still acumulating in the wheel well. It seems apparent to me, and several others who have complained about the same issue, that the recall fix has not addressed the main issue of why the water is coming in and why it's still not draining. Unfortunately we're going to have to fork over $1200 to have it fixed. My ask to the federal safety agency is that this issue be readdressed with Mercedes. I would like them to be notified that the recall does not address the underlying issues and the solution they provided does not fix the problem. I appreciate your time in considering this.

Filed Apr 14, 2024 · Body, Electrical · UT

Vehicle will not crank/start intermittently key turns in the ignition but nothing happens. Front door on the right and left will not operate and have to push down locks in order for vehicle to lock and prevent vehicle/ property theft.

Filed Mar 12, 2020 · Airbags, Electrical · NY

I put my key into the ignition and it would not start. I had a tow truck to come and get my vehicle and they charged the vehicle and would not go into neutral or drive. I know that I probably need a new battery but this was scary.

Filed Jun 29, 2018 · Electrical · NJ

When attempting to start the vehicle the car does not start and the dashboard lights do not illuminate. It usually takes multiple tries before it usually does start. Has been going on for months.

Filed Oct 11, 2016 · Electrical · TX

Eis the key will lock/unlock car, will turn in ignition but will not start car

Filed Jul 26, 2016 · Electrical · TX

There was a service campaign no. 2013040001, issued april, 2013 from daimler ag, the manufacturer of mercedes- benz vehicles, for models 164 , x164, 251, model years 2011-2012. It stated that "due to a supplier process issue the electronic ignition switch does not correspond to specification which may lead to a no start condition when turning the key." I am the second owner of this vehicle, purchased december, 2014. Sunset auto sales purchased this vehicle in december, which is my husband's car lot. The vehicle was doing this randomly and dealership could not find fault code. Dealership had to replace ignition switch july 22, 2016 and invoice states " found eis to be defective. Replaced eis and problem no longer detected at this time." I contacted mercedes customer care service to have this repair compensated and was told my vehicle was not in the recall, there wasn't any recall for the eis, and they didn't know how my vehicle had been taken care of and would not compensate for this. I was not aware of any method to take care of vehicle that would care for the eis. My vehicle year and model was included in this campaign, that had no end date, I might add. I explained that being stranded because of a no start situation would not be good, given my medical condition. I feel because the ignition switch is a documented defect, described in the service campaign letter with no end date, mercedes should have compensated me for this expense.

Filed Feb 29, 2016 · Electrical · 57,913 miles · CA

While vehicle is stationary, turning key in the ignition switch may or may not start the vehicle or turning key in ignition may experience a delay before vehicle will start or it may require turning the key in the on and off position several times before starting. After a no start situation, it may take several minutes before vehicle will finally start.

Filed Mar 2, 2013 · Engine, Fuel system · 21,200 miles · CA · crash

My wife was driving my ml350 on the freeway with my 7 year old son in the back. She said the vehicle started to shake in an unusual way so she decided to get off at the nearest exit and when she applied the brakes on the off ramp the car's engine stopped. Engine light came on, dash read inoperable yet all the electrical was still on. She tried to turn the key and restart it but the car would not start. Before this incident we had not experienced any problems. This is a 2012 model with just over 21,000 miles and was just serviced two weeks prior to the incident . It happened all of a sudden. The car was hit by another vehicle- rear ended with both my wife and son still in it.

Filed Feb 26, 2013 · Electrical · 19,000 miles · MA

Was driving to work on the highway in the rain and the truck jerked over to the right without me doing it. Its happened three more times since then. The dealership cannot duplicate the problem so therefore there is no problem. My ignition switch needed to be replaced at 20,000 miles. My keys would not start the truck for an entire week straight on the 1st or 2nd attempt. Finally on the 3rd try the truck would start. Its a year and a half old. When they connected it to they're computer it did not read any error codes. It had to not start there for it to code. Now my truck is back in the shop because the gear shift gets stuck in p. I asked to get out of the lease and into another one of their vehicles because the car is unsafe to drive and the answer was no. Because the computer says there is nothing wrong with it. I guess its normal when your on the highway for your truck to change lanes without your consent.