When operating an E-ONE vehicle (like fire apparatus or emergency vehicles) with a Cummins ISL engine, the emissions aftertreatment system cannot be compromised. A key component in that system is the DEF (Diesel Exhaust Fluid) head unit. The E-ONE Cummins ISL DEF Head Unit, built to OEM specification 5142426-01, monitors and controls critical fluid parameters. If this module fails or drifts out of calibration, your system may register errors, warnings, or even force an engine derate at an inopportune time.
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Tracks DEF fluid level, temperature, and urea concentration, supplying accurate data to the vehicle’s ECU
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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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Designed to meet OEM 5142426-01 tolerances for plug-and-play compatibility with E-ONE / Cummins ISL platforms
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Helps prevent fault codes, emissions warnings, and engine derates that stem from sensor drift or inaccurate feedback
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Built for durability in emergency service environments: vibration resistance, thermal cycling, and exposure to DEF chemistry
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Facilitates faster replacement or servicing, minimizing apparatus downtime
In fire or emergency service, reliability isn’t just desirable—it’s essential. Installing the correct OEM 5142426-01 DEF head unit restores the integrity of your emissions feedback loop, keeps your SCR system functioning properly, and reduces the risk of unexpected system failures. When performance and compliance are nonnegotiable, this is one component you’ll want to trust.




























































































































































































































































































