Cummins DEF Doser Pump Unit | PN 5506956

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The Cummins DEF Doser Pump Unit (5506956) precisely meters and pumps diesel exhaust fluid to the SCR aftertreatment system in Cummins-powered trucks including ISX15, ISX12, and ISB6.7 applications. The DEF pump maintains the correct pressure and flow rate required for the SCR system to achieve EPA-compliant NOx reduction. A failing DEF pump causes SCR system faults, progressive engine derate, and emissions non-compliance. This genuine Cummins OEM replacement restores full aftertreatment function.

Q: Which trucks and engines does this DEF pump fit?
A: Fits Cummins ISX15, ISX12, and ISB6.7 diesel engines. Genuine Cummins part number 5506956.

Q: What fault codes indicate a failing DEF doser pump?
A: Common codes include SPN 3031 (DEF pump failure) and SCR system low pressure faults in Cummins Insite diagnostic software.

Q: What happens if the DEF doser pump fails completely?
A: The SCR system stops functioning, triggering progressive engine derate — the engine speed and power are reduced incrementally until the system is repaired.

Q: Is this a genuine Cummins part?
A: Yes. This is a genuine Cummins OEM DEF doser pump — using genuine parts ensures proper system pressure and SCR catalyst protection.

Q: What is included with this DEF pump?
A: Includes the complete Cummins DEF doser pump assembly 5506956 ready for installation.