
+ applicable tax
Solve your "Low DEF Pressure" or "Reductant Metering" fault codes. This is the Genuine OEM DEF Dosing Module for Caterpillar Tier 4 Interim and Final engines — the exact same unit that Cat re-boxes and sells as their own for nearly $1,000.
Your DEF (Diesel Exhaust Fluid) injector sits directly on the exhaust pipe, spraying urea into the exhaust stream. Because it is exposed to extreme exhaust heat and crystallizing fluid, it fails in two ways:
When the dosing injector fails, the SCR system cannot reduce NOx emissions. The ECU detects this and puts your machine into Derate Mode — first reducing power by 25%, then eventually forcing a complete shutdown.
Replace the failed dosing injector with this Genuine OEM Denoxtronic 2.2 unit. It's the identical part that came on your machine from the factory. Caterpillar does not manufacture DEF injectors — they purchase them from the original equipment supplier and re-label them. The "Denoxtronic 2.2" marking is visible on the black plastic housing.
This is the coolant-cooled version. Please ensure you clamp your coolant lines before removal to minimize fluid loss. The coolant circuit prevents the DEF from crystallizing inside the injector during operation.
This dosing injector fits all Caterpillar machines equipped with the Denoxtronic 2.2 emissions system. If your parts manual lists 424-4205, 460-9256, or 383-9377, this is the correct replacement.
My DEF injector is clogged. Can I clean it instead of replacing it?
You can try soaking the nozzle tip in warm distilled water, but if the metering valve has failed electronically or the internal passages are crystallized, cleaning will not restore proper function. A new OEM unit is the reliable fix.
Do I also need to replace the DEF pump filter?
Yes, we strongly recommend it. When the dosing injector fails, it is often because the pump filter was dirty, allowing contaminated DEF to reach the injector. Replacing the filter kit prevents the new injector from failing prematurely.
Is this the same part Perkins sells as T401183?
Yes. Caterpillar and Perkins use the same Denoxtronic 2.2 dosing module. The Cat 424-4205 and Perkins T401183 are the identical OEM part.
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Save 38%OEM Denoxtronic 2.2 DEF Dosing Module for Caterpillar Tier 4 engines. Direct replacement for Cat 424-4205, 460-9256, 383-9377, and Perkins T401183. Solves low DEF pressure and reductant metering fault codes. Coolant-cooled — plug-and-play installation.
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