The DEF doser injector is a critical component of the Selective Catalytic Reduction (SCR) aftertreatment system on Tier 4 Final / Stage V Cummins engines. It precisely meters and injects Diesel Exhaust Fluid (DEF/AdBlue) into the exhaust stream to reduce NOx emissions to regulatory compliance levels. When it fails, you'll trigger SCR fault codes, DEF system warnings, and — if left unresolved — engine derate or shutdown. This is a new original Cummins doser injector covering part numbers 4394644 and 0444B05704, engineered to restore precise DEF dosing and keep your aftertreatment system in full compliance.

✅ Direct-Fit Compatibility

• Cummins Engines: B4.5, D4.0, F3.8, F4.5
• Emissions Platforms: CM2350 B146C, CM2620 B158B, CM2620 B180B, CM2620 D103B
• Direct replacement — no modifications required

🔧 Product Highlights

• New Original Cummins OEM: Genuine factory unit — not aftermarket or remanufactured
• Precise DEF Dosing: Correct spray pattern and flow rate for accurate SCR catalyst dosing and NOx reduction
• Clears SCR Fault Codes: Restores proper aftertreatment system operation and eliminates DEF-related engine derate risk
• Direct Drop-In Fit: No modifications required; installs like the original
• Dual Cross-Reference: Covers both 4394644 and 0444B05704 (Bosch) for confirmed fitment
• Emissions Compliance: Maintains Tier 4 Final / Stage V regulatory compliance for your equipment

📦 What's Included

• 1 × New Original Doser Injector (4394644 / 0444B05704)

🔑 Key Specs

• Part Numbers: 4394644, 0444B05704
• Condition: New Original (OEM)
• Fitment: Cummins B4.5 / D4.0 / F3.8 / F4.5 engines (CM2350 / CM2620 platforms)
• System: SCR Aftertreatment / DEF Dosing

Please verify your engine serial number, emissions platform, and existing part number before ordering. Contact us for fitment confirmation if needed.