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Fault Code Reference

SPN 4072 FMI 0Aftertreatment

Aftertreatment 1 Fuel Pressure 1 - Data Valid But Above Normal

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Overview

Fault Code

SPN 4072 / FMI 0

Category

Aftertreatment

Derate Risk

No

Regen Inhibit

No

Inducement Risk

No

Component Location: Aftertreatment fuel pressure sensor is located on the doser fuel supply line, typically mounted near the DPF or doser injector assembly on the exhaust aftertreatment module.

Common Symptoms

  • Check engine light illuminated
  • Excessive DEF consumption
  • Incomplete or failed regenerations
  • White smoke from exhaust during regen
  • Engine derate or power loss
  • Frequent active regeneration requests

Root Causes

  • Stuck-open or leaking doser injector allowing excessive fuel pressure buildup Faulty or sticking fuel pressure regulator/control valve in the doser fuel supply circuit Restricted or blocked fuel return line causing pressure to rise above normal range Failed or out-of-calibration aftertreatment fuel pressure sensor reporting falsely high values Air in the doser fuel supply system causing erratic high pressure readings Doser pump running at excessive output due to control circuit fault Contaminated fuel or debris restricting return flow and elevating supply pressure Wiring short to voltage on the fuel pressure sensor signal circuit causing falsely elevated reading

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Derate Behavior

Power Derate

No

Mileage / Regen Notes

SPN 4072 FMI 0 indicates aftertreatment doser fuel pressure is above normal operating range. This condition will typically inhibit active DPF regeneration to prevent doser flooding, over-fueling, or potential thermal damage. If inhibit persists, soot loading may increase and the system may enter a parked or forced regen lockout state depending on OEM logic.

System Interactions

SPN 4072 FMI 0 interacts with the following systems and may trigger cascading faults if not resolved promptly.

DPF differential pressure monitoring — soot load calculations affected
SCR NOx conversion efficiency — DEF dosing strategy may be altered
Active regen inhibit logic — regen may be blocked or delayed
Engine protection derate — ECM may reduce power to protect components

Common Diagnostic Mistakes

Replacing the sensor without verifying wiring continuity and supply voltage first.

Clearing codes without identifying and resolving the root cause — the fault will return.

Ignoring related active faults — cascading faults often share a root cause.

Skipping the connector inspection — corrosion and damaged pins are a leading cause of sensor faults.

Condemning the ECM before exhausting all wiring and component tests.

Replacing the DPF without verifying the regen system is functional — a failed regen injector will reload the new DPF.

Ignoring DEF quality — contaminated DEF causes SCR efficiency faults that look like hardware failures.

Deep-dive diagnostic page: SPN 4072 FMI 0 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.

Authority References

Diagnostic procedures on this page are informed by OEM service literature and industry standards.

EPA Aftertreatment & Emissions GuidelinesU.S. EPA heavy-duty diesel aftertreatment compliance, DPF/SCR regulations, and NOx standards.Cummins QuickServe OnlineOfficial Cummins service manuals, fault code lookup, and TSB database.Detroit Diesel DiagnoCentralDetroit Diesel diagnostic procedures, DDDL documentation, and service literature.PACCAR MX Engine ServicePACCAR MX-11 and MX-13 engine service documentation and DAVIE diagnostic guides.Volvo/Mack Tech ToolVolvo and Mack engine fault code reference and PTT/Tech Tool diagnostic procedures.ASE — Diesel Truck Technician CertificationNational Institute for Automotive Service Excellence — T2 Diesel Engines certification standards.

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