In modern diesel systems, every sensor has a job—and one of the most critical is the DEF (Diesel Exhaust Fluid) head unit. For Blue Bird buses equipped with Cummins ISB 6.7L / B6.7 engines, the DEF head ensures your aftertreatment system runs clean, accurate, and trouble-free. When that head fails, your emission system, diagnostics, and driveability can suffer, which is the last thing you want with children onboard.
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Monitors DEF fluid level, temperature, and urea concentration, sending precise feedback to the engine control module
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Regulates exact dosing of DEF into the exhaust so the SCR (Selective Catalytic Reduction) system can reduce NOx emissions effectively
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Designed to OEM tolerances for Blue Bird / Cummins ISB / B6.7 configurations, enabling plug-and-play replacement
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Helps prevent fault codes, check engine alerts, or engine derates that often result from failing or out-of-spec sensors
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Built to endure vibration, temperature cycling, and exposure to corrosive DEF chemistry
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Field-friendly design promotes quicker swap-outs and minimal downtime
School buses run on tight schedules, and emission faults are disruptive. Installing the correct DEF head restores integrity to your emissions feedback loop, keeps your SCR system running smoothly, and helps avoid surprise maintenance events. When the safety and reliability of your fleet matter, this is one component you don’t want to overlook.