SPN 27 FMI 6EGRMedium
EGR Valve Position Sensor - Current Above Normal
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 27 / FMI 6
Category
EGR
Severity
Medium
Derate Risk
Sometimes
Regen Inhibit
No
Inducement Risk
No
Component Location: EGR valve is mounted on the intake side of the engine, typically near the intake manifold and connected to the exhaust system.
Common Symptoms
- EGR valve stuck or not responding to commands
- Active fault code SPN 27 FMI 6 logged in ECM
- Rough idle or unstable engine operation
- Increased NOx emissions
- Engine derate or reduced power
- MIL or CEL illuminated
- Failed emissions test
Root Causes
- Short circuit to ground or voltage in EGR valve position sensor signal circuit
- Damaged or chafed wiring harness causing overcurrent condition
- Failed EGR valve position sensor with internal short
- Corroded or moisture-contaminated connector at EGR valve
- Failed EGR valve actuator with integrated sensor short
- ECM driver circuit overcurrent due to sensor wiring fault
- Incorrect sensor installed or wrong part number
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Derate Behavior
Power Derate
Sometimes
Mileage / Regen Notes
Short circuit — inspect wiring before replacing sensor.
System Interactions
SPN 27 FMI 6 interacts with the following systems and may trigger cascading faults if not resolved promptly.
TSB Reference: EGR position 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
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 27 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.
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