2021 Ford F-250 Super Duty Problems: 3 Known Issues

On the 2015-2022 Ford F-250 Super Duty 6.7L Power Stroke Diesel, the Selective Catalytic Reduction (SCR) system on 2015-2022 6.7L Power Stroke trucks - which uses Diesel Exhaust Fluid (DEF) to reduce NOx emissions - is prone to failure, most commonly triggering DTC codes P207F (Reductant Quality Performance) and P20EE (SCR NOx Catalyst Efficiency Below Threshold). Causes include degraded or crystallized DEF fluid (DEF has a shelf life of 1-2 years and degrades faster in heat), a failed DEF injector, SCR catalyst failure, DEF quality sensor failure, or NOx sensor failure. In limp mode, the truck's performance is severely limited. The system is complex and diagnosis requires a professional scan tool. The DEF injector is a particularly common failure point on 2017+ trucks.

On the 2011-2022 Ford F-250 Super Duty 6.7L Power Stroke Diesel, the 6.7L Powerstroke diesel engine exhaust manifold studs are prone to breaking due to thermal cycling. The extreme heat cycles of the diesel exhaust cause the studs to fatigue and snap, creating an exhaust leak at the manifold-to-head junction. This produces a ticking noise on cold starts that may diminish when warm, exhaust smell in the cabin, and can trigger check engine lights for exhaust leaks. The driver side manifold is more commonly affected.

On the 1999-2025 Ford F-250 Super Duty, the factory steering damper on the F-250 Super Duty wears out and fails, leading to increased steering shimmy, vibration at highway speeds, and reduced ability to dampen road imperfections. The single factory damper is often inadequate for the weight and solid front axle of the Super Duty. A worn damper does not cause death wobble directly but removes the last line of defense against oscillation. Most factory dampers are worn out by 50,000-80,000 miles.