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Fault Code Reference

SPN 100 FMI 0Medium

Engine Oil Pressure - Above Normal (High)

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Overview

Fault Code

SPN 100 / FMI 0

Severity

Medium

Regen Inhibit

No

Inducement Risk

No

Component Location: Engine oil pressure sensor is typically located on the engine block near the oil filter housing or main oil gallery, accessible from the side of the engine.

Common Symptoms

  • Engine oil pressure gauge reading higher than normal
  • Active fault code logged in ECM
  • Possible engine warning light illuminated
  • Sluggish oil pressure relief valve behavior
  • Cold start high pressure that does not normalize at operating temperature

Root Causes

  • Stuck or malfunctioning oil pressure relief valve (closed or restricted)
  • Incorrect viscosity oil installed (too thick)
  • Faulty or out-of-calibration oil pressure sensor sending artificially high reading
  • Blocked or restricted oil passages causing pressure buildup
  • Oil pressure sensor circuit short to voltage causing false high reading
  • Cold start with high-viscosity oil not yet warmed to operating temperature
  • Incorrect oil filter installed or filter anti-drain valve malfunction causing restriction

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Derate Behavior

Mileage / Regen Notes

Often sensor fault or cold-start condition; verify with mechanical gauge

System Interactions

SPN 100 FMI 0 interacts with the following systems and may trigger cascading faults if not resolved promptly.

TSB Reference: OEM oil system TSBs

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.

Deep-dive diagnostic page: SPN 100 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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