SPN 193 FMI 0Fuel
Fuel Rail Pressure Too Low
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Connector Pinout — in guided session
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Overview
Fault Code
SPN 193 / FMI 0
Category
Fuel
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: High-pressure fuel pump and fuel rail assembly are typically mounted on the engine block or cylinder head, with the fuel pressure sensor on the fuel rail.
Common Symptoms
- Engine lacks power under load
- Hard starting or extended cranking
- Rough idle or engine misfiring
- White or gray smoke from exhaust
- Engine derate or limp mode
- Check engine light illuminated
Root Causes
- Faulty fuel pressure regulator or control valve Worn or failing high-pressure fuel pump Leaking fuel injector or injector seal Restricted fuel filter or supply line Air in the fuel system
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Derate Behavior
Power Derate
Yes
System Interactions
SPN 193 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
Diagnostic Engine v7.0
Related Diagnostic Articles
Deep-dive diagnostic page: SPN 193 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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