SPN 500 FMI 0Sensors
Vehicle Speed Sensor A
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 500 / FMI 0
Category
Sensors
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: Vehicle speed sensor is typically mounted on the transmission output shaft or rear axle differential housing.
Common Symptoms
- Speedometer reading higher than actual vehicle speed
- ABS/traction control malfunction or disabled
- Cruise control inoperative or erratic
- Transmission shifting issues or harsh shifts
- Engine overspeed protection activating prematurely
- Erratic or fluctuating speedometer needle
Root Causes
- Faulty vehicle speed sensor Damaged or corroded wiring harness to speed sensor Intermittent connector issues at sensor or ECM Incorrect tone ring or reluctor installation ECM internal fault
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Derate Behavior
Power Derate
No
System Interactions
SPN 500 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
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 500 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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