The 2022 Ford F-250's 6.7L Power Stroke diesel relies on Diesel Exhaust Fluid (DEF) for emissions compliance. When DEF system faults occur, the truck can enter reduced power mode and eventually limit speed if not addressed.
Understanding the DEF System
DEF is injected into the exhaust where it converts NOx emissions to harmless nitrogen and water through the Selective Catalytic Reduction (SCR) catalyst. The system monitors DEF quality, level, and injection rate continuously.
Common DEF System Problems
DEF Quality Sensor Failure
The quality sensor can fail or become contaminated, incorrectly reporting poor DEF quality. Code P20EE indicates the reductant quality doesn't meet expected performance.
DEF Crystallization
DEF can crystallize in lines, the injector nozzle, or tank when exposed to air or extreme temperatures. Crystals block flow and cause system faults.
DEF Injector Clogging
The injector that sprays DEF into the exhaust can clog from crystallization or contamination, preventing proper dosing.
Contaminated DEF
DEF contaminated with fuel, coolant, oil, or other substances triggers quality warnings. Even small contamination percentages cause system faults.
Speed Limiting Countdown
Ford's emissions compliance system progressively limits performance: first warnings, then torque reduction, and eventually 5 MPH maximum speed until repairs are made.