SPN 441 FMI 0EVAPLow
Evaporative Emission System Incorrect Purge Flow
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 441 / FMI 0
Category
EVAP
Severity
Low
Regen Inhibit
No
Inducement Risk
No
Component Location: The EVAP purge valve and canister are typically located near the fuel tank or in the engine bay with vapor lines routing between them.
Common Symptoms
- MIL (Check Engine Light) illuminated
- Failed emissions/OBD readiness test
- Fuel odor near engine or fuel tank area
- Rough idle or idle fluctuation during purge cycle
- Reduced fuel economy
- Hard start or extended crank time
Root Causes
- Faulty or stuck-closed EVAP purge solenoid valve Cracked, kinked, or disconnected EVAP purge hose/line Failed or leaking EVAP canister Plugged or restricted EVAP canister vent valve Carbon buildup blocking purge flow path
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Derate Behavior
Mileage / Regen Notes
SPN 441 FMI 0 on light-duty or medium-duty general EVAP systems does not typically inhibit DPF regen directly; however, active MIL may inhibit OBD regen readiness monitors from completing.
System Interactions
SPN 441 FMI 0 interacts with the following systems and may trigger cascading faults if not resolved promptly.
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.
Related Faults in This Category
OEM System Resources
ASE Training Resources
Diagnostic Engine v7.0
Related Diagnostic Articles
Deep-dive diagnostic page: SPN 441 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.
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.EPA Aftertreatment & Emissions GuidelinesU.S. EPA heavy-duty diesel aftertreatment compliance, DPF/SCR regulations, and NOx standards.
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