Freightliner Cummins ISB 6.7L, ISL, L9 DEF Head Unit

DEF System Precision for Freightliner Cummins – OEM DEF Head Unit (04‑35649‑002), 2018‑2021

What is it?
The OEM 04‑35649‑002 DEF Head Unit is an emission‑system component designed for Freightliner trucks equipped with Cummins ISB 6.7L, ISL, or L9 engines (model years 2018–2021). It attaches to the top of the DEF tank and houses sensors that monitor fluid level, temperature, and integrate with the vehicle’s SCR system.

Why choose this OEM DEF Head Unit?
Built to the exact specifications of Cummins and Freightliner, this head unit ensures accurate sensor outputs, proper sealing, and direct compatibility with OEM diagnostics and control systems. Using the genuine unit helps avoid DEF faults, false alarms, leaks, or system interruptions that often occur with non‑OEM alternatives.

Key Benefits
 ✅ Drop‑in fit for Freightliner Cummins ISB 6.7L, ISL, L9 (2018‑2021)
 ✅ Accurate DEF fluid level and temperature sensing
 ✅ Correct sealing to prevent fluid leaks and protect system integrity
 ✅ Maintains compatibility with factory diagnostics and SCR systems
 ✅ Durable construction suited for heavy‑duty thermal and operational stress

Applications
Ideal for Freightliner trucks using Cummins ISB 6.7L, ISL, or L9 engines in lines including regional haul, municipal service, vocational, or delivery applications where DEF functionality and emission control are essential.

Installation Notes
Have a trained technician handle installation. Begin by depressurizing or disabling the DEF system. Clean the DEF tank opening and remove any debris or corrosion. Replace seals and O‑rings before installing the new head unit to specifications. After mounting, verify sensor readings, check for leaks, and clear any DEF or SCR fault codes via diagnostics.

Final Thoughts
If your Freightliner’s DEF system is throwing level warnings, erratic readings, or sensor faults, the OEM 04‑35649‑002 DEF Head Unit restores factory-accurate monitoring and system stability. With the genuine part, you get compatibility, longevity, and peace of mind for proper DEF operation.