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Fault Code Reference

SPN 3244 FMI 11AftertreatmentInducement Risk

Aftertreatment 1 DEF Doser 1 Absolute Pressure - Root Cause Not Known

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Overview

Fault Code

SPN 3244 / FMI 11

Category

Aftertreatment

Derate Risk

Yes

Regen Inhibit

No

Inducement Risk

Yes — SCR inducement possible

Component Location: DEF doser and pressure sensor are located on or near the DEF decomposition tube/mixing pipe in the aftertreatment system, typically mounted on the exhaust mid-pipe between DPF and SCR catalyst.

Common Symptoms

  • Check engine light illuminated
  • DEF system malfunction warning
  • Reduced engine power or derate
  • DEF dosing may be inhibited
  • Aftertreatment system efficiency codes may accompany this fault

Root Causes

  • DEF doser injector clogged or failed due to crystallized urea buildup DEF supply pump pressure out of specification or failed DEF pressure sensor failed or out of calibration Air ingestion in DEF lines causing erratic pressure readings Collapsed or kinked DEF supply line restricting flow DEF filter clogged restricting pressure to doser ACM software or calibration issue requiring update Wiring harness chafing or connector corrosion at DEF doser or pressure sensor DEF quality issue causing crystallization and blockage DEF tank low or empty causing pump cavitation

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Derate Behavior

Power Derate

Yes

SCR Inducement Risk

If left unresolved, this fault may trigger SCR inducement — a progressive derate enforced by the ECM to ensure emissions compliance.

Mileage / Regen Notes

SPN 3244 FMI 11 may inhibit or suspend active DPF regeneration events as the ACM cannot confirm proper DEF dosing pressure, preventing SCR system operation and potentially triggering derate conditions depending on OEM strategy.

System Interactions

SPN 3244 FMI 11 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 3244 FMI 11 — 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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