When rugged off-road machines or specialty vehicles use a Cummins engine under heavy demands, one of the often underappreciated components in the emissions chain is the DEF (Diesel Exhaust Fluid) head unit. The Oshkosh Cummins DEF Head Unit, built to OEM 3350459 specifications, integrates multiple sensors and pathways to keep your DEF system honest. When it fails or falls out of calibration, you risk system faults, error codes, and potential engine derates—problems nobody wants in the field.
-
Combines multiple sensing functions—fluid level, temperature, and urea concentration—into one compact module
-
Manages precise dosing of DEF into the exhaust stream so the SCR system can effectively reduce NOx emissions
-
Built to OEM 3350459 tolerances, ensuring drop-in compatibility and proper calibration with Oshkosh / Cummins systems
-
Helps prevent emissions warning codes, system faults, and engine derates caused by sensor drift or failure
-
Designed with a 40-micron filter to protect downstream injectors and components from contamination
-
Engineered to endure harsh operational environments—vibration, temperature swings, and chemical exposure
-
Offered with a robust warranty (one million miles or one year) to back reliability
A failing DEF head unit often slips under the radar until it triggers a warning or diagnostic alert. By installing a properly matched, OEM-quality replacement, you restore the integrity of your emissions feedback loop, protect your engine’s aftertreatment system, and eliminate surprises on the job. For Oshkosh machines powered by Cummins, this module quietly ensures your emissions system stays clean, accurate, and dependable.