SPN 2291 FMI 0DPFInducement Risk
DPF Differential Pressure Sensor Range/Performance
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 2291 / FMI 0
Category
DPF
Derate Risk
Possible
Regen Inhibit
No
Inducement Risk
Yes — SCR inducement possible
Component Location: The DPF differential pressure sensor is typically mounted on the engine or chassis near the DPF, with hoses connecting to inlet and outlet ports on the filter.
Common Symptoms
- Check engine light illuminated
- DPF regeneration cycles more frequent than normal
- Engine derate or power reduction
- Excessive exhaust backpressure warning
- Poor fuel economy
Root Causes
- Faulty DPF differential pressure sensor Clogged or partially blocked DPF pressure sensing lines Excessive soot loading in the DPF Carbon buildup or contamination in pressure sensor ports Damaged or kinked pressure hoses between DPF and sensor
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Derate Behavior
Power Derate
Possible
SCR Inducement Risk
If left unresolved, this fault may trigger SCR inducement — a progressive derate enforced by the ECM to ensure emissions compliance.
System Interactions
SPN 2291 FMI 0 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
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 2291 FMI 0 — 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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