If you operate a transit bus or fleet vehicle built on a Gillig chassis with a Cummins ISL engine, your emissions system is always under pressure. One of the least visible—but most vital—components is the DEF (Diesel Exhaust Fluid) head unit. The Gillig Cummins ISL DEF Head Unit (OEM 82-71776-001) carries the responsibility of sensing your DEF’s state and dosing it precisely. When it fails, the system may throw error codes, force derates, or even trigger shutdowns—and your rider service suffers.
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Checks DEF tank level, temperature, and urea concentration continuously, supplying accurate data to the engine’s control module
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Controls precise dosing of DEF into the exhaust stream so the SCR (Selective Catalytic Reduction) system can reduce NOx emissions effectively
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Designed to OEM 82-71776-001 tolerances, ensuring correct fit, calibration, and system integration for Gillig / Cummins ISL setups
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Helps prevent emissions warnings, fault codes, and engine derates triggered by sensor drift, errors, or misreads
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Built rugged enough for transit use—withstanding vibration, temperature fluctuations, and exposure to DEF’s chemical properties
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Field-friendly replacement minimizes downtime, helping you return buses to service faster
Because fleet downtime costs more than parts, the DEF head unit deserves more attention than it commonly gets. By choosing the correct OEM 82-71776-001 Gillig Cummins ISL DEF Head Unit, you restore the accuracy of your emissions feedback loops, stabilize your SCR system, and ward off unexpected shutdowns. In fleet service, this “small” component frequently determines whether everything else performs as promised.