If your vehicle or machine is built on a Capacity chassis with a Cummins ISB 6.7L engine, your emissions system depends heavily on accurate feedback and dosing. The Capacity Cummins ISB 6.7L DEF Head Unit (OEM 911181, Tamerx part 4310-18-1) is a linchpin component that monitors fluid level, temperature, and urea concentration, while controlling flow into the SCR system. When that head is off—even slightly—you risk warning codes, emissions faults, or even system derates.
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Monitors DEF fluid parameters — level, temperature, and urea concentration — sending reliable signals to the engine control unit
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Regulates precise dosing of DEF into the exhaust stream so the SCR (Selective Catalytic Reduction) system can reduce NOx emissions effectively
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Built to meet the OEM 911181 standard for plug-and-play integration with Capacity / Cummins ISB 6.7L systems
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Helps prevent fault codes, warning lights, and engine derates triggered by sensor drift or inaccurate readings
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Constructed to withstand real-world stress: vibration, thermal cycling, and exposure to DEF chemistry
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Includes filtration (approx. 40 microns) to protect downstream injectors and components from contamination
A failing or mis-calibrated DEF head unit is often the silent culprit behind emission system errors. Installing the correct OEM 911181 Capacity Cummins ISB 6.7L DEF Head Unit restores sensor integrity, stabilizes your SCR circuit, and helps keep your machine emission-compliant and dependable. In the emissions chain, this small component plays an outsized role—don’t let it become your weak link.