Operating a Navistar or International rig with a Cummins ISX15 (or X15) engine means you depend heavily on your aftertreatment system to stay compliant—and that places significant importance on one component: the DEF (Diesel Exhaust Fluid) head unit. A properly functioning DEF head ensures the engine control module receives accurate fluid readings and doses, which helps prevent fault codes, system warnings, or engine derates.
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Measures DEF fluid properties including temperature, level, and urea concentration and feeds that information back to the ECU
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Manages precise DEF dosing into the exhaust stream to ensure the SCR (Selective Catalytic Reduction) system can effectively reduce NOx emissions
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Designed to OEM tolerances for ISX15 / X15 applications—meaning it’s built for direct fit and calibration
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Helps avoid emissions fault codes, check engine alerts, and derate conditions that often stem from sensor inaccuracies
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Built durable to withstand vibration, thermal cycling, and exposure to DEF fluid’s corrosive elements
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Users can replace it in the field with minimal downtime, restoring system integrity
When signs of trouble emerge—like a “DEF system error” or unexpected engine derate—the DEF head is often the underlying culprit. Installing a correct, matching DEF Head Unit for your Navistar / International Cummins ISX15 / X15 helps maintain consistent emissions performance, prevent surprise faults, and keep your rig road-ready. Don’t let a failing sensor become the bottleneck in your emissions system.