2021 Ford F-350 SD Problems

What owners report

Owners of this model year mostly write about the 6.7L diesel fuel system, especially the high-pressure fuel pump, and many complaints are tied to an open recall for that pump with no remedy yet available. Reports range from a reduced-power message and stalling on the road to fuel leaking around the upper filter, and they cluster from roughly 30,000 to 200,000 miles. A smaller share of complaints covers electrical glitches, tailgate and camera problems, and wiper failures tied to a separate recall.

1. 1
   Fuel system

   High-pressure diesel fuel pump failure and stalling

   • 37 complaints (38%)
   • median 108,000 mi at 4.3 yrs old (17 state mileage)
   • filed 2021–2026

   Complaints describe the truck losing power while driving, sometimes with a reduced-power or low-power message and a check engine light, then failing to restart. Dealers and independent shops have diagnosed high-pressure fuel pump failure, and several owners say the pump sent metal debris through the rest of the fuel system, requiring the whole system to be replaced. Many of these complaints were filed after owners received recall notices for the pump but were told parts or the software remedy were not yet available. Spread from about 30,000 to 200,000 miles, with many reports in the 100,000 to 130,000 mile range; often while driving or towing.

   Recall 24V957000Recall 26V158000Recall 25V4550002 related service bulletins

   What to check: Ask whether the high-pressure fuel pump recall work was performed and with which parts, and request service records for any pump or fuel system replacement. On a diesel truck, check for a fuel smell, look for leakage around the upper fuel filter, and ask about the maintenance history of the fuel filters.

   2 excerpts from owner complaints in NHTSA records

   “I was driving my truck home when it completely shut off, I lost all power to everything, including the power steering brakes. When I got home, I did some research on the Internet to see possible causes. Apparently there is a service bulletin for the fuse box having water getting into it from the cowl of the hood, which states it can do exactly what happened to my truck? You can also keep your truck running and not shutting off and just to hold host of other safety issues with the service bulletin. . …”

   NHTSA complaint #11749077, filed 2026-07

   “The high pressure fuel pump failed sending metal shavings through out the entire fuel system. I had no heads up and the failure left me stranded on top of a bridge. I called 911 twice and finally the cops showed up and wrecker towed me off the bridge. Ford is aware of this known issue with this make and model, and even put a recall partial recall / quick fix to increase the flow around the pump to keep it cooler. I had the quick fix recall completed but it did not prevent the failure and me being stranded on a bridge.”

   NHTSA complaint #11761855, filed 2026-09
2. 2
   Electrical system

   Moisture in battery junction box causing electrical faults

   • 7 complaints (7%)
   • median 121,100 mi at 2.9 yrs old (4 state mileage, few)
   • filed 2022–2026

   Complaints describe the truck shutting off completely while driving or failing to shut off with the start/stop button, sometimes with multiple warning lights. Owners report that dealers traced this to water getting into the battery junction box or fuse box, and one owner points to a corroded plug above the spare tire causing numerous codes and loss of climate control, windows and blind spot monitoring. Trailers dropping out of detection and warning messages about the trailer connection also appear in complaints. Reported from about 44,000 to 195,000 miles, often after rain or wet conditions.

   3 related service bulletins

   What to check: Look for water stains or corrosion around the fuse box and under the cowl, and check the wiring plug above the spare tire. Ask whether any water-intrusion repairs or software updates for the blind spot and trailer systems were done.

   2 excerpts from owner complaints in NHTSA records

   “Upon starting the vehicle I get precollision not available warning light and hill decent control fault hill assist warning. Service steering and antilock brake brake fault lights. The dealer has looked at it but they said can not duplicate it. The problem is when I am towing my fifth wheel trailer and this happens it shuts down the brake controller for the fifth wheel and it’s VERY hard to stop the truck and trailer”

   NHTSA complaint #11684074, filed 2025-08

   “While driving my 21 F350 my truck would go into limp mode. The climate control stopped working, passenger window stopped, blind spot monitors, along with the mirror. After running forscan it showed every code possible. After an exhaustive search I finally found the main plug under the bed just above the spare tire. The wires inside of the insulation had corroded away to the point it had to be stripped back at least 1/2 inch before getting decent wires that wouldn't crumble when touched. …”

   NHTSA complaint #11596800, filed 2024-06
3. 3
   Fuel system

   Diesel fuel leak from upper fuel filter area

   Mentioned in 5 of 60 sampled complaints

   Owners describe diesel leaking from the top of the secondary fuel filter, in some cases in large enough quantity that the truck could not be driven. Complaints mention the upper filter leaking and dealers identifying the filter cap or filter housing as the source, with fuel system repairs recommended. One recall for this model year addresses a possible pinhole in the secondary fuel filter cap that allows fuel to leak. Reported mostly between roughly 100,000 and 180,000 miles, and described as sudden rather than gradual.

   Recall 22V0130001 related service bulletin

   What to check: Inspect the filter housing and cap area under the hood for diesel residue or a fuel smell, and ask whether the secondary fuel filter cap recall was completed.

   2 excerpts from owner complaints in NHTSA records

   “This truck on a daily basis, shuts down with out warning. Check engine light comes on some time, some times get P0191, P0171 and other codes dealing with fuel rail and pressure. Vehicle had less than 10000 miles when started. Dealer don't know what to do. Shuts off when you are in a turn and leaves you with out steering, and shuts off when coming to a stop sign, or trying to park. Fuel filters have been changed 2 times in 2 months. Truck is not safe to drive because it keeps surging and cutting off. …”

   NHTSA complaint #11440834, filed 2021-11

   “The contact owns a 2021 Ford F-350. The contact received notification of NHTSA Campaign Number: 24V957000 (FUEL SYSTEM, DIESEL); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact stated that the upper fuel filter had been leaking diesel fuel. …”

   NHTSA complaint #11639053, filed 2025-01, 180,000 miles
4. 4
   Back-over prevention (rear camera)

   Rearview camera blank, blurry or unavailable

   Mentioned in 4 of 60 sampled complaints

   Owners report the backup camera showing a black screen, a blurry image, or an unavailable-camera message, and dealers diagnosing a failed wiring harness or camera. Several complaints were filed in connection with recalls covering the rearview camera image, and some owners were told the remedy was not yet available or that no open recall applied to their truck. Mostly reported between roughly 90,000 and 130,000 miles, but some owners describe it from the start of ownership.

   Recall 25V048000Recall 25V6860001 related service bulletin

   What to check: Put the truck in reverse and look at the display in different lighting. Ask whether the rearview camera recalls were completed and whether the camera or its wiring harness has been replaced.

   2 excerpts from owner complaints in NHTSA records

   “The contact owns a 2021 Ford F-350. The contact stated when the vehicle was shifted into reverse(R), the back-up camera image was blurry. The contact wiped the camera lens; however, the image remained blurry. The contact had not taken the vehicle to a local dealer. The vehicle was not diagnosed or repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 93,000.”

   NHTSA complaint #11624786, filed 2024-11, 93,000 miles

   “The contact owns a 2021 Ford F-350. The contact stated that the back over prevention camera had been inoperable since purchasing the vehicle. The contact had received notification of NHTSA Campaign Number: 25V048000 (BACK OVER PREVENTION); however, the VIN tool showed no open recall. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The failure mileage was 110,000.”

   NHTSA complaint #11729638, filed 2026-04, 110,000 miles

Buying note. Check the recall status for the diesel high-pressure fuel pump and confirm whether any remedy has actually been applied, since many complaints are about the wait for parts or software. Also review service records for fuel system repairs and walk around the truck looking for fuel leaks and water intrusion before buying.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.