Which parts fail
Components named in complaints (fuel pump, injectors, fuel tank, hybrid and EV propulsion).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2009 Mercury Mariner owners, lightly cleaned up (personal details are redacted by NHTSA).
Tl* the contact owns a 2009 Mercury Mariner. The contact stated that he could smell a strong, abnormal gas odor upon exiting the vehicle. The contact stated that the odor was the strongest when the gas tank was full. The contact took the vehicle to an independent mechanic who informed him that there was a leak at the top of the fuel tank. He was informed that the fuel tank needed to replaced. The manufacturer was notified of the failure and informed him that the VIN was not under recall. A dealer was not notified of the failure. The manufacturer referred the contact to NHTSA for assistance. The vehicle was not repaired. The failure mileage was approximately 154,000.
On 1/1/2016 I was driving on 495 w in queens, ny heading back to manhattan where I live. Out of nowhere the car began jerking, a wrench light on the dash panel came on (which I never saw before) and I could tell the car was decelerating. I tried hitting the accelerator again, the car would jerk, the engine was revving but was barely moving. I knew I had to pull over and luckily I was able to navigate to the shoulder of the road. This was an extremely dangerous situation. I am a confident driver, however, a less confident or timid driver most likely would have panicked and gotten into a potentially serious collision.
While unit is running on road engine still running car stop for absent of power but engine keep running, pressing gas pedal will do anything , you have to turn engine off wait and turn engine on back in order to kept driving , this very dangerous because this happens in the middle of the hay way at any speed , please consider a recall we almost get kill by a rear impact if we did react fast . Update does not fix situation, this a troubleshooting from factory and they now this very clear. This happens in hay way 147 going north to south at 9.10 pm on 06/13/2018 where we were driving speed limits of 55mph.
While in motion the car will stall causing me to pull off to the side of the road, turn the car off, then back on in order for it to work again. This happens every 10-15 miles and its really unsafe! I believe it is a defective throttle body and needs to be fixed asap before I can continue driving it.
The vehicle randomly shuts down while operating on the highway between 65-75 MPH. There is no warning and it becomes very difficult to steer the car. After waiting for 10 to 15 minutes the engine can be restarted and all seems to operate, until it happens again.
Charcoal canister and purge valve defective stuck at open. Check engine light, dropped fuel economy. Forced vehicle to shut off engine and no power, stop on freeway at full speed.
Was driving down country road and all of a sudden felt then engine what I thought was kick out of gear. Had no acceleration at all. Pulled off road and the vehicle was running in a rough idle, but still could not give it gas. Once placed in park the idle leveled out and still no acceleration. The wrench symbol was on. I stopped the engine and waited 10 minutes then restarted engine and everything was OK. For about 3 months. I took into the Ford dealer only to be told there was no code and they could do nothing without it. Problem has gotten steadily worst. And now it is at point where wife can not drive her car! I am driving it and finally yesterday the engine light came on. I ran it to autozone where they confirmed the dreaded p2112 code. I took it to the Ford dealer today figuring alright less than 5 years old and 42,000 miles I would finally get it fixed. No go! …
On October 18, 2018 I received the power steering assist failure error on my instrument panel when turning on my vehicle. I had driven it earlier in the day without issue. Previously I had the occasional warning noise and quick flash of an error (too quick for me to read all the way) and would have momentary difficulty turning. This issue makes it almost impossible to steer the vehicle. Research indicates that it is most likely a malfunctioning torque sensor. I reached out to Ford after learning of recalls for the 2009 model year. I was informed that my VIN was not included in the recall. Ford was unwilling to assist with the cost of repairs in any way. Their suggestion was to keep the receipt on the slim chance that the recall would be expanded. This is unacceptable. Had I been on a highway when this occurred it could have been fatal to myself or others. …
2009 Mercury Mariner with about 90,000 miles. Was on the freeway driving about 65-70 MPH when suddenly the power to car cut off - was not able to accelerate vehicle; drove to right side of the road. Car was still on, but gas pedal would not work, wrench light was on, car idling very roughly. Turned car off. Turned car back on, wrench light was off, drove another 30 minutes to destination without incident. In the two hour drive home, the car cut off five more times. I heard a bell alert audio sound a few times, but the only light that came on was the wrench just as the power cut off. The very last time it happened, the engine light came on, and stayed on even after restarting the car. I feel very thankful to have got home alive and without getting into an accident. …
While entering interstate highway, engine balked like bad gas. After two or three tankfuls and the vehicle dying in traffic, I left it with my dealer to find the problem. After a week, the vehicle had not died for them so I brought it home, only to continue with the same dying and hesitating when accelerated. A month or so later the dealer kept it again for about 5 days and it still did okay for them. They have no idea what the "problem" is. We have parked the car in our garage because several times we have narrowly escaped being rear-ended, when turning corners, crossing railroad tracks, etc. I contacted Ford motor co. In michigan and they do not "have this problem with other vehicles" and don't seem to know what I'm talking about. Mechanics in two other garages have driven the vehicle and have not located the problem. Help!!
Fuel System complaints in other Mariner years
Frequently asked questions
How common are fuel system problems on the 2009 Mercury Mariner?
NHTSA has 30 complaints about the fuel & propulsion system of the 2009 Mercury Mariner, 10% of the model year's 315 complaints. The component named most often is storage › tank assembly (1 mentions).
Is there a recall for 2009 Mercury Mariner fuel system problems?
No. NHTSA lists no fuel & propulsion system recall for the 2009 Mercury Mariner, though it has 1 recall for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2009 Mercury Mariner fuel system problems start?
Half of the complaints with a recorded mileage happened before about 73,000 miles, and 7% before 25,000 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.