SPN 4236 FMI 16EGR
EGR Valve Control - Data Valid But Above Normal
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Overview
Fault Code
SPN 4236 / FMI 16
Category
EGR
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: EGR valve assembly is mounted on the intake side of the engine, typically on or near the EGR cooler outlet and intake manifold connection, accessible from the top or front of the engine.
Common Symptoms
- Check engine light illuminated
- Engine derate or reduced power
- Increased exhaust smoke
- Poor fuel economy
- Rough idle or hesitation
- EGR system fault code active
Root Causes
- EGR valve stuck open or mechanically binding in open position Excessive EGR valve carbon buildup causing valve to remain partially open EGR valve actuator failure — not responding to ECM close commands EGR cooler restriction or failure causing backpressure affecting valve control Faulty EGR position sensor reporting falsely high position signal Wiring harness short to voltage on EGR valve control or position signal circuit ECM software or calibration issue causing incorrect EGR valve command Intake manifold pressure sensor fault causing ECM to over-command EGR flow Exhaust backpressure sensor fault providing incorrect feedback to ECM
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Derate Behavior
Power Derate
Yes
Mileage / Regen Notes
SPN 4236 FMI 16 (EGR valve above normal operational range) may inhibit or delay active DPF regeneration. An EGR valve stuck open increases EGR flow, which can lower combustion temperatures and interfere with the elevated exhaust temperatures required for regen initiation. The ECM may suppress regen requests until EGR control is restored within normal operating limits. Parked regen attempts may be blocked if this fault is active.
System Interactions
SPN 4236 FMI 16 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 4236 FMI 16 — 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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