SPN 2659 FMI 5EGRMedium
EGR Valve Control - Current Below Normal
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Connector Pinout — in guided session
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Overview
Fault Code
SPN 2659 / FMI 5
Category
EGR
Severity
Medium
Derate Risk
Sometimes
Regen Inhibit
No
Inducement Risk
No
Component Location: EGR valve is typically mounted on the intake manifold or EGR cooler outlet on the engine, accessible from the top or side of the engine block.
Common Symptoms
- EGR valve fails to respond or actuate
- Illuminated Check Engine / MIL light
- Reduced engine power or derate condition
- Increased NOx emissions
- Rough idle or unstable engine operation
- Failed emissions test
- DPF regeneration issues due to altered exhaust temps
Root Causes
- Open circuit in EGR valve actuator wiring harness
- Broken or corroded connector pins at EGR valve harness connector
- Failed EGR valve actuator motor (internal open circuit)
- Damaged or chafed wiring between ECM and EGR valve
- Blown fuse in EGR valve control circuit
- Poor ground connection at EGR valve or ECM
- ECM driver circuit failure (less common)
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Derate Behavior
Power Derate
Sometimes
Mileage / Regen Notes
Active and parked DPF regeneration may be inhibited due to altered exhaust gas temperature and flow profiles caused by EGR valve malfunction; regen inhibit or extended regen intervals are common.
System Interactions
SPN 2659 FMI 5 interacts with the following systems and may trigger cascading faults if not resolved promptly.
TSB Reference: EGR valve 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 2659 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.
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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