SPN 411 FMI 6EGRMedium
EGR Differential Pressure Sensor - Current Above Normal
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
DieselVision™ Upload photos — DieselVision™ reads diagrams, connectors, and screens with precision.
Overview
Fault Code
SPN 411 / FMI 6
Category
EGR
Severity
Medium
Derate Risk
Sometimes
Regen Inhibit
No
Inducement Risk
No
Component Location: The EGR differential pressure sensor is typically mounted on or near the EGR cooler or intake manifold to measure pressure across the EGR system.
Common Symptoms
- Active fault code for SPN 411 FMI 6 stored in ECM
- EGR system operation reduced or disabled
- Possible engine derate or power reduction
- Increased NOx emissions
- Failed emissions test
- Possible rough idle or unstable engine operation
Root Causes
- Short to ground on signal wire causing current above normal condition
- Failed EGR differential pressure sensor with internal short
- Chafed or damaged wiring harness causing short to ground or power
- Corroded or water-intruded sensor connector
- Faulty ECM driver circuit for sensor supply
Full step-by-step tests, DVOM guidance, and pinout data are available inside the AI Diesel Tech diagnostic session.
AI walks you through every test — one step at a time. Plans start at $12.95/mo.
Derate Behavior
Power Derate
Sometimes
Mileage / Regen Notes
EGR differential pressure fault may inhibit or limit active DPF regeneration events; ECM may restrict regen if EGR flow cannot be verified, increasing DPF soot loading risk.
System Interactions
SPN 411 FMI 6 interacts with the following systems and may trigger cascading faults if not resolved promptly.
TSB Reference: EGR delta P TSB
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 411 FMI 6 — 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.
Get weekly diesel diagnostic tips
Real-world fault code walkthroughs, wiring tips, and shop-tested fixes — free.
No spam. Unsubscribe anytime.
Get AI-Guided Diagnosis for SPN 411 FMI 6
The diagnostic engine walks you through every physical test — step by step, on your phone, at the truck. No guessing. No wasted parts.