Out in heavy-duty yard or terminal service, reliability is king—and that applies just as much to your emissions components as your powertrain. The TICO Tractors Cummins DEF Head Unit (OEM 620840) is one of those parts that usually flies under the radar—but when it works right, it keeps your DEF (Diesel Exhaust Fluid) system accurate, compliant, and resilient. A fail here can cascade into warnings, derates, and unwanted downtime.
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Measures DEF fluid parameters: level, temperature, and urea concentration, sending clean signals to the ECU
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Regulates proper dosing of DEF into the exhaust stream to allow the SCR (Selective Catalytic Reduction) system to reduce NOx emissions efficiently
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Designed to OEM 620840 standards, giving you drop-in compatibility with TICO / Cummins setups
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Helps prevent fault codes, emission warnings, engine derates caused by bad sensor readings or drift
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Built for durability—able to stand up to vibration, temperature swings, and DEF’s corrosive nature
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Simplified replacement process to minimize service time
If your terminal tractor or yard equipment is throwing DEF system errors or running into emissions trouble, the DEF head is often one of the first suspects. By installing the correct OEM 620840 TICO Tractors Cummins DEF Head Unit, you restore accurate sensing, protect your SCR system, and reduce the risk of surprise maintenance stops. It’s a small component—but its impact on uptime and compliance is anything but small.
























































