SPN 1173 FMI 16Engine Protection
Engine Oil Filter Differential Pressure - Data Valid But Above Normal
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1173 / FMI 16
Category
Engine Protection
Derate Risk
Yes
Regen Inhibit
No
Inducement Risk
No
Component Location: Oil filter and differential pressure sensor are located on the engine block, typically on the driver side mid-engine area.
Common Symptoms
- Engine warning light illuminated
- Engine derate or power reduction
- Oil pressure gauge reading higher than normal
- Oil filter housing warm to the touch
- Reduced fuel economy
Root Causes
- Clogged or restricted oil filter Wrong oil filter installed High viscosity oil or wrong oil grade Oil filter differential pressure sensor malfunction Excessive sludge buildup in oil system
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Derate Behavior
Power Derate
Yes
System Interactions
SPN 1173 FMI 16 interacts with the following systems and may trigger cascading faults if not resolved promptly.
ECM communication — J1939 network faults can affect all connected modules
Engine protection — ECM may trigger derate to prevent damage
Aftertreatment — engine protection derates can affect regen strategy
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 1173 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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