SPN 100 FMI 18EngineHigh
Engine Oil Pressure - Low
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Overview
Fault Code
SPN 100 / FMI 18
Category
Engine
Severity
High
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: Oil pressure sensor is typically located on the engine block near the oil filter housing or main oil gallery, varies by OEM and engine family.
Common Symptoms
- Low oil pressure warning lamp illuminated, audible alarm or chime, engine derate with reduced power, MIL/CEL on, possible engine knock or ticking noise at idle, oil pressure gauge reading low or erratic, engine may shut down if pressure drops critically low, sluggish performance under load
Root Causes
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Derate Behavior
Power Derate
Yes
Mileage / Regen Notes
Active DPF regeneration is typically NOT inhibited directly by this fault, but engine protection logic may limit RPM and load required for regen. If engine enters severe derate or limp mode due to critically low oil pressure, regen will not complete. Address oil pressure issue first — running extended regens with marginal oil pressure increases risk of engine damage.
System Interactions
SPN 100 FMI 18 interacts with the following systems and may trigger cascading faults if not resolved promptly.
TSB Reference: No confirmed universal TSBs — verify in OEM service portal. Cummins: Check for oil pressure sensor calibration updates on ISX/X15. Detroit: Check for DD13/DD15 oil pump drive gear TSBs. Paccar: Check for MX-13 oil cooler housing leak bulletins. Always search by engine serial number for applicable campaigns.
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 100 FMI 18 — 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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