SPN 412 FMI 6EGRMedium
EGR Temperature Sensor - Current Above Normal
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 412 / FMI 6
Category
EGR
Severity
Medium
Derate Risk
Sometimes
Regen Inhibit
No
Inducement Risk
No
Component Location: EGR temperature sensor is mounted directly on the EGR cooler outlet or EGR pipe downstream of the cooler, typically on the driver side of the engine near the intake manifold.
Common Symptoms
- Active fault code SPN 412 FMI 6 logged in ECM
- EGR temperature reading stuck at maximum or erratic high value
- Possible engine derate or power reduction
- Illuminated MIL or Check Engine light
- DPF regen may be inhibited or delayed
- EGR valve operation may be affected or disabled
Root Causes
- Short circuit to ground or supply voltage in EGR temperature sensor signal wire
- Failed EGR temperature sensor with internal short
- Chafed or damaged wiring harness causing short to ground
- Corroded or moisture-contaminated sensor connector causing leakage current
- Failed or intermittent ECM driver circuit for EGR temperature sensor
- Pinched wiring harness near exhaust or EGR cooler causing insulation breakdown
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Derate Behavior
Power Derate
Sometimes
Mileage / Regen Notes
Short circuit — inspect wiring before replacing sensor.
System Interactions
SPN 412 FMI 6 interacts with the following systems and may trigger cascading faults if not resolved promptly.
TSB Reference: EGR temp 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 412 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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