Detroit Diesel Fault Code

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SPN 3480 FMI 2

Parked Regen Fails / Low Doser Press

System

Fuel System / Regen

Symptom

Parked Regen Fails / Low Doser Press

Diagnosis & fix steps

LOGIC: Hydrocarbon (HC) Doser Fuel Line Pressure Low / Erratic. ACTION: Inspect HC doser block screen for carbon plugging. Replace HC doser valve and check fuel supply pressure regulator on doser manifold.

Red Seal field insights

Thermal Regen Link: The MCM uses the HC doser valve to inject raw fuel into exhaust stream upstream of DOC to raise regen temperatures.

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