If your fleet vehicle uses a Capacity chassis powered by the Cummins ISB 6.7L engine, the emissions system hinges on more than major modules—it depends on subtle control parts. The DEF (Diesel Exhaust Fluid) head unit built to the OEM 911181 standard monitors and manages fluid flow, concentration, and temperature for the SCR (Selective Catalytic Reduction) system. When this module drifts out of calibration or fails entirely, expect fault codes, dosing irregularities, or emissions non-compliance to creep in.
-
Tracks DEF fluid level, temperature and urea concentration, feeding accurate data to the engine control module
-
Controls the precise dosing of DEF into the exhaust stream, enabling the SCR catalyst to convert NOx efficiently
-
Engineered to fit the Capacity / Cummins ISB 6.7L setup with OEM 911181 calibration and plug-and-play compatibility
-
Helps prevent common fault symptoms like SCR system error codes, inconsistent dosing warnings, or engine derates caused by sensor drift
-
Built to withstand vehicle duty: vibration, thermal cycling, and exposure to DEF’s corrosive environment
Installing the right DEF head unit isn’t just about emissions—it’s about maintaining system integrity and uptime. By choosing the correct OEM 911181 unit, you restore the accuracy of your feedback loop, support clean engine operation, and help your fleet stay ready for service. In today’s emission-regulated landscape, precision counts—and this part is where it starts.























































































































































































































































































