Fuel System complaints by model year
Which parts fail
Components named in complaints (fuel pump, injectors, fuel tank, hybrid and EV propulsion).
Mileage when the problem started
What owners report
Tl* the contact owns a 2009 Mercedes-Benz ML320. After fueling the vehicle, the contact noticed that the vehicle was leaking fuel badly. The fire department removed some of the fuel before the vehicle was towed. The failure recurred four times. The vehicle was towed to a dealer where it was diagnosed that the fuel sender needed to be replaced. The vehicle was repaired; however, the failure recurred. The manufacturer was notified of the failure. The approximate failure mileage was 58,000.
Check engine light warning with code #20be1b. Repair indicates need of diesel exhaust fluid (def) heater repair kit. Diesel exhaust fluid system is part of emissions system. Mb dealership says no warranty for repair. Internet research widespread problem with def system around 50,000 miles.
My ML320 vehicle was driven for approximately five hours round trip then parked for the evening. I attempted to start the vehicle the following morning and the vehicle would not start. After doing an exhaustive diagnostic on the vehicle. I removed the fuel pump from inside the fuel tank. I saw that the wiring harness/connector for the hot lead was black and brown in color and the plastic around the harness had melted. I took pictures and stored the pump. I emailed Mercedes and asked them to get back with me since my wife and children had been in the vehicle and this is the family vehicle. I also read several forums and complaints on the internet reference Mercedes fuel pumps including my specific model. I read how they have caught on fire. I also saw a picture of a fuel pump out of a ml 320 in 2006 that had caught fire and almost looked identical to my fuel pump I had removed. …
Reference odi 10457817 I have since received a letter from Mercedes corp. Stating the fuel pump fire is due to age and normal wear and tear. I asked how a fire inside a fuel tank can be normal for any reason. They would only repeat that it was normal for the age of the vehicle. I cannot get rid of the vehicle right now for financial reasons . However I don't have to let my family ride in it. Please help because this is not right. I have the letter from mb stating the above.
As I noticed in other complaints they all focus in the power steering issues, fuel / oil leaks and loss, ESP option , electrical mail functions that relate with the ECU, problem with the shifter. All these are safety concerns since all the above problems can cause an accident . I have the same problems in my car and it is really difficult to operate the vehicle. The power steering is not working as the car is not in speed motion unless you use strength to turn the wheel , the ESP is not working at all , the shifter is not changing to drive unless you override it and that's the only way to start it and the fuel along with the oil is leaking and all the fluids are disappearing in no time . All these are safety hazards and not just a simple problem . …
The method in which a fuel tank is fastened to the vehicle chassis uses a steel strut to support a series of stainless steel straps. The dissimilarity in metals used in fastening the hardware of both combined with exposure to the elements will cause the strut to corrode without warning and the fuel tank to drop onto the roadway without prior symptoms or warning. The corrosion at the critical fasting points is not obvious with routine inspection. With many of these vehicles manufactured from 1998 through 2005 still on the road today, owners should be made aware of this potential safety issue.
This is in regard to NHTSA id #10033607, also Mercedes Benz service campaign #2009100002 dated jan 2010, for model 163. My vehicle isn't covered by above Mercedes service campaign because it's v-6 model, but showing exactly the same safety problem. I've taken and attached a few photos of the problem area showing severe damage to fuel line and less so to brake line. The photos showing severe chafing between fuel line & brake line just below master cylinder. The service campaign only covers 8 cylinder models, but my 6 cylinder model is showing exactly the same chafing at the same area. I have not experienced any problem, but just noticed this issue last few days.
The computer let the consumer know that brake pads were defective, while taking the vehicle out on a test drive caliper locked up. Prior to this happening vehicle was starting in third gear, instead of first gear. It difficult to move out in traffic. Dealer/mechanic experienced the same problem, and replaced the fuel pump, and fuel line.
Frequently asked questions
Which Mercedes-Benz ML320 years have fuel system problems?
By NHTSA complaints, the 1998 (20), 2000 (16), 1999 (14), 2001 (11) and 2009 (9) model years. Fuel System complaints make up 15% of all complaints for the 1998.
Is there a recall for Mercedes-Benz ML320 fuel system problems?
No. NHTSA lists no fuel & propulsion system recall for any Mercedes-Benz ML320 model year. A widespread problem may still be covered by an extended warranty or a manufacturer service bulletin, so ask a dealer.
At what mileage do Mercedes-Benz ML320 fuel system problems start?
Across all years, half of the complaints with a recorded mileage happened before about 66,000 miles; 38% happened before 50,000 miles.
What part fails most often?
Owners most often name the delivery › fuel pump (18 mentions), followed by the storage › fuel gauge system (8).
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.