4377650 | Genuine OEM Cummins DEF Doser Injector

The 4377650 Genuine OEM Cummins DEF Doser Injector is a component of the diesel exhaust fluid (DEF) dosing system. It delivers DEF into the exhaust aftertreatment system to support selective catalytic reduction (SCR) and emissions control.

PRODUCT INFORMATION

Part Number: 4377650
Brand: Cummins
Condition: Not specified
Component: DEF Doser Injector
Fuel Type: Diesel
Engine Applications: Cummins ISB and QSB engines
Other Specifications: DEF dosing component for the SCR aftertreatment system

APPLICATIONS

The 4377650 DEF Doser Injector is associated with Cummins ISB and QSB engine applications. Actual compatibility depends on the engine configuration and emissions system. Verify the original part number before purchasing.

FUNCTION

The DEF doser injector introduces diesel exhaust fluid into the exhaust stream. The fluid supports the SCR system in reducing nitrogen oxide (NOx) emissions as part of the engine's exhaust aftertreatment process.

A worn, damaged, or failing DEF doser injector may cause symptoms such as:

• DEF dosing system fault codes
• Check engine or emissions warning lights
• SCR system efficiency faults
• Excessive DEF consumption
• DEF crystallization or deposits around the dosing area
• Reduced engine power or engine derate

WHY REPLACE A DEF DOSER INJECTOR?

A faulty DEF doser injector can interfere with correct fluid delivery and affect exhaust aftertreatment performance. Replacing a confirmed defective injector with the correct part can help restore proper DEF dosing and support SCR system operation.

FITMENT INFORMATION

Before purchasing the 4377650 DEF Doser Injector, verify the Part Number, VIN, vehicle model, engine, and emissions system configuration. Part number supersessions and variations may exist, so confirm that this part matches your original equipment.

If you are unsure whether this part is correct for your vehicle, please contact us with your VIN and original part number. We are happy to help verify compatibility before purchase.

GENUINE CUMMINS PART

Part Number: 4377650