Oshkosh Cummins DEF Head Unit

DEF System Reliability for Oshkosh: OEM DEF Head Unit (4202057)

What is it?
The OEM 4202057 DEF Head Unit is the original equipment component that attaches to the top of the DEF (Diesel Exhaust Fluid) tank in Oshkosh vehicles. It includes the level (and where applicable, temperature or quality) sensor(s) needed to manage the DEF system properly under SCR (Selective Catalytic Reduction) requirements.

Why choose this OEM DEF Head Unit?
Manufactured to Oshkosh/Cummins factory specifications, this unit ensures correct sensor alignment, sealing, and compatibility with the vehicle’s electronic control systems. Choosing the OEM version helps avoid faulty sensor signals, leaks, or warning lights that often arise from aftermarket, non‑spec components.

Key Benefits
 ✅ Direct OEM fit for Oshkosh DEF systems
 ✅ Accurate fluid level monitoring (and other sensor functions)
 ✅ Proper sealing to prevent leaks and maintain DEF integrity
 ✅ Compatible with original DEF wiring and diagnostics to avoid error codes
 ✅ Built for rugged use in demanding environments

Applications
Ideal for Oshkosh vehicles equipped with DEF systems—especially in municipal, emergency, military, or heavy service roles—where reliable emissions control and system monitoring are essential.

Installation Notes
Install while DEF system is off and tank is secure. Clean mounting area and inspect for seal or O‑ring integrity. Replace old gasket/seals, torque to OEM specifications. After installing, verify sensor readings and clear any DEF system error codes via diagnostics.

Final Thoughts
For Oshkosh fleets or operators seeing DEF warnings, sensor faults, or fluid level issues, the OEM 4202057 DEF Head Unit offers the dependable performance and compatibility needed to restore proper DEF system operation and emissions compliance.