The 2022 Chevrolet Silverado 2500's Duramax diesel depends on a properly functioning DEF system for emissions compliance. DEF system faults trigger warnings and can progressively limit vehicle performance.
Duramax DEF System Components
The system includes the DEF tank with level and quality sensors, a delivery pump, heated lines, injector, and the SCR catalyst. All components must work together for proper NOx reduction.
Common DEF Faults
Quality Sensor Failure
Code P20EE indicates reductant quality performance. The sensor may fail internally or become contaminated, reporting incorrect quality readings.
DEF Heater Problems
DEF freezes at 12°F. Heaters in the tank and lines prevent freezing. Failed heaters in cold climates cause system malfunction when DEF can't flow.
Pump Module Failure
The DEF pump module contains the pump, filter, and sensors. Module failures prevent proper DEF delivery to the injector.
Injector Clogging
Crystallized DEF or debris can clog the injector nozzle, preventing proper dosing into the exhaust stream.
Reduced Power Progression
GM's system progressively limits power then eventually speed if DEF faults aren't resolved, ensuring the vehicle returns for service.