SPN 3719 FMI 11AftertreatmentInducement Risk
Aftertreatment 1 Diesel Exhaust Fluid Doser - Failure Mode Not Identifiable
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Overview
Fault Code
SPN 3719 / FMI 11
Category
Aftertreatment
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
Yes — SCR inducement possible
Component Location: DEF doser injector is mounted on the DEF decomposition tube upstream of the SCR catalyst, typically mid-frame or on the exhaust aftertreatment assembly.
Common Symptoms
- Active fault code logged with no clear failure pattern
- DEF dosing intermittently interrupted or halted
- SCR efficiency degradation or NOx slip increase
- MIL or CEL illuminated
- Possible derate or torque reduction
- Intermittent or erratic DEF doser operation
Root Causes
- DEF doser injector internal failure or coking Intermittent or corroded wiring harness connector at doser DEF supply line restriction or air ingestion causing erratic dosing ACM software anomaly or calibration mismatch DEF quality issue causing deposit buildup in doser tip DEF pump delivering inconsistent pressure to doser ECM/ACM internal fault or communication error
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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 3719 FMI 11 may inhibit or interrupt DEF dosing, reducing SCR conversion efficiency. Active dosing faults can trigger forced DPF regen inhibit or derate conditions depending on OEM calibration and NOx aftertreatment strategy.
System Interactions
SPN 3719 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.
Related Faults in This Category
OEM System Resources
ASE Training Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 3719 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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