SPN 3610 FMI 5AftertreatmentInducement Risk
Doser Injector Driver Circuit - Current Below Normal or Open Circuit
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Overview
Fault Code
SPN 3610 / FMI 5
Category
Aftertreatment
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
Yes — SCR inducement possible
Component Location: Doser injector is mounted on the aftertreatment system DPF inlet or DOC outlet pipe, typically under the cab or mid-chassis on the exhaust system.
Common Symptoms
- Check engine light illuminated
- DEF system malfunction indicator active
- Insufficient DEF dosing or no dosing occurring
- Failed NOx conversion efficiency
- SCR system inefficiency fault codes present
- DEF consumption significantly reduced or zero
Root Causes
- Open circuit in doser injector wiring harness between ACM and injector connector
- Corroded or damaged doser injector electrical connector
- Failed doser injector solenoid (open coil winding)
- Broken or chafed wiring in the aftertreatment harness
- Poor ground connection at the ACM or aftertreatment module
- Blown fuse or open circuit protection device in the doser injector circuit
- ACM internal driver circuit failure
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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
An open circuit on the doser injector driver circuit (FMI 5) will inhibit DEF or fuel dosing, preventing active DPF regeneration. The ACM will typically block initiated and forced regens, and DPF soot load will continue to accumulate. High soot load derate conditions may follow if fault is not resolved.
System Interactions
SPN 3610 FMI 5 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 3610 FMI 5 — 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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