Freightliner Cummins ISL, ISX15 DEF Head Unit

Emissions Control Confidence for Freightliner Cummins – OEM DEF Head Unit (04‑31677‑001), 2014‑2016

What is it?
The OEM 04‑31677‑001 DEF Head Unit is a factory header assembly designed for Freightliner trucks equipped with Cummins ISL or ISX15 engines during model years 2014 to 2016. This unit mounts on the DEF tank and houses sensors that monitor fluid level and temperature—ensuring accurate Diesel Exhaust Fluid delivery and SCR emissions system integration.

Why choose this OEM DEF Head Unit?
Constructed to Cummins and Freightliner factory specifications, this unit ensures precise sensor calibration, reliable sealing, and seamless compatibility with the vehicle’s DEF system electronics. By choosing the genuine OEM part, you avoid common issues such as sensor faults, leaks, inconsistent DEF readings, or SCR system errors that may accompany non‑OEM components.

Key Benefits
 ✅ Direct-fit for Freightliner trucks using Cummins ISL or ISX15 (2014‑2016)
 ✅ Precise monitoring of DEF fluid level and temperature
 ✅ Sealed design to maintain DEF integrity and prevent leaks
 ✅ Fully compatible with OEM diagnostic systems and SCR control
 ✅ Durable construction to withstand operational demands

Applications
This head unit is intended for Freightliner vehicles powered by Cummins ISL or ISX15 engines within the 2014–2016 range. It is especially useful in Class 8 tractors, vocational trucks, and regional fleets that depend on reliable SCR/DEF functionality for emissions compliance.

Installation Notes
A qualified technician should install the unit. Begin by depressurizing or isolating the DEF system. Clean the DEF tank opening and service the mounting surface. Replace any worn O‑rings or gaskets. Install the head unit and torque it to OEM specifications. Once mounted, verify sensor readings using diagnostic tools, check for leaks, and clear any DEF or SCR fault codes to confirm correct operation.

Final Thoughts
If your Freightliner truck with an ISL or ISX15 engine is experiencing DEF sensor faults, warning lights, or erratic readings, upgrading to the OEM 04‑31677‑001 DEF Head Unit restores accurate level sensing and emissions system stability. As a factory-spec replacement, it keeps your vehicle compliant, dependable, and on the road.