Most common 2009 Mercedes-Benz ML320 problems
Share of the 28 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Mercedes-Benz ML320 complaints by model year
Best ML320 years: 2005, 2007, 2008. Years to avoid: 1998, 2000, 1999, 2001, 2002. Compare all years →
2009 Mercedes-Benz ML320 recalls (3)
Service brakes, hydraulic › Power assist › Vacuum
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2006-2012 ML, GL, and R-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. Moisture may accumulate and cause corrosion in the brake booster housing unit, which can result in reduced brake performance or brake failure.
Remedy: Owners are advised not to drive their vehicles until the remedy has been performed. Dealers will remove the rubber sleeve, inspect the brake booster, and as necessary, replace the brake booster.
Service brakes, hydraulic › Power assist › Vacuum
Mercedes-Benz USA, LLC (MBUSA) is recalling certain 2006-2012 ML-Class, GL-Class, and R-Class vehicles. Please refer to MBUSA's recall report for specific vehicle model details. Moisture may accumulate and cause corrosion in the brake booster housing unit, which can result in reduced brake performance or brake failure.
Remedy: Owners are advised not to drive their vehicles until the remedy has been performed. Dealers will remove the rubber sleeve, inspect the brake booster, and as necessary, replace the brake booster.
Air bags › Frontal › Driver side › Inflator module
Mercedes-Benz USA, LLC. (MBUSA) is recalling certain model year 2009-2010 ML320 BlueTec 4Matic, GL320 BlueTec 4Matic and R320 CDI 4Matic, 2011 E350 Cabriolet and E550 Cabriolet, 2009-2011 ML350, ML350 4Matic, ML550 4Matic, ML63 AMG, and C63 AMG, 2010-2011 ML450 4Matic Hybrid, E350 Coupe, E350 4Matic, E550 Coupe, E550 4Matic,…
Remedy: MBUSA will their notify owners, and Fiat Chrysler will notify the affected Chrysler owners. Dealers for the respective brands will replace the driver's frontal air bag module, free of charge.
NHTSA defect investigations
Federal safety investigators have looked into a possible defect involving the 2009 Mercedes-Benz ML320:
Desiccated Air Bag Inflator Rupture
From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited.
What 2009 Mercedes-Benz ML320 owners say
Fuel & propulsion system
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.
Engine & cooling
Our vehicle caught fire. My wife and I had just gotten off of the interstate when we started to smell an odd smell. We pulled into a hotel parking lot where we started to see smoke coming from the front of the vehicle. I stopped the vehicle in a hotel driveway, put the vehicle in park. We got out of the vehicle and saw flames underneath the vehicle. We called 911 and hotel staff tried to extinguish the fire but it continued to grow. The fire dept. Arrived and put out the fire. Photos are attached.
Tl* the contact owns a 2009 Mercedes Benz ML320. While driving approximately 60 MPH, the vehicle stalled without warning. The vehicle restarted after several attempts. The vehicle was taken to an independent mechanic who stated that the camshaft position sensor failed and needed to be replaced. The vehicle was repaired. The manufacturer was made aware of the failure. The approximate failure mileage was 60,000. Updated 4/30/15 the consumer also stated the glow plug control unit, heat element and door lock failed. Updated 05/07/15
Transmission & drivetrain
Tl* the contact owns a 2009 Mercedes Benz ML320. The contact stated that while going approximately 5 MPH, the vehicle hesitated to shift into gear. The engine would rev and the vehicle would not respond. The contact then shifted into gear and the vehicle accelerated rapidly. The vehicle was taken to the dealer for inspection and the contact was informed that the failure was unable to be determined. The failure recurred several times later and the contact took the vehicle back to the dealer for another inspection where they informed the contact that the transmission module software needed to be updated. The vehicle was repaired but the failure recurred. The manufacturer was contacted but the contact had not received a response. The failure mileage was 45,000.
ML320 bluetec, randomly loses power. The power will be restored once the car is turned off and on again. Car has been to the dealer 7 times for repair of this one issue, including twice in a state with limited power. Dealer has done multiple software updates, turbo replacement, exhaust valves replacement and the issue is still present. On one of the last occasions this happened, the car lost power when trying to merge on to the hwy. This almost resulted in me being rear ended by a big rig. Luckily I was able to pull to the shoulder before I was rear ended. This is serious safety concern that needs to be addressed and rectified. As of 02/17/2014 this issue has not been corrected.
Frequently asked questions
Is the 2009 Mercedes-Benz ML320 a good car?
Based on 28 owner complaints filed with NHTSA, the 2009 ML320 rates better than average: 56% fewer complaints than a typical year of the ML320 at the same age. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2009 Mercedes-Benz ML320?
The fuel & propulsion system — 9 complaints, 32% of all complaints for this model year. Next are the engine & cooling (9) and transmission & drivetrain (4).
How many recalls does the 2009 Mercedes-Benz ML320 have?
There are 3 recalls for the 2009 Mercedes-Benz ML320, the most recent from April 26, 2024 (vacuum). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Mercedes-Benz ML320?
The best years by complaints, compared at the same age, are 2005, 2007 and 2008. Years to avoid or approach with caution: 1998, 2000, 1999, 2001 and 2002. See the full Mercedes-Benz ML320 years comparison.
At what mileage do 2009 Mercedes-Benz ML320 problems happen?
The median mileage reported in complaints is about 58,000 miles; 45% of problems with a recorded mileage started before 50,000 miles.
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.