SPN 1250 FMI 10ABS
Wheel Speed Sensor - Trailer Axle 1 Right - Abnormal Rate of Change
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1250 / FMI 10
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The wheel speed sensor is mounted at the right wheel end of the first trailer axle, typically integrated into the hub assembly or mounted on the brake spider.
Common Symptoms
- ABS warning lamp illuminated on trailer
- Trailer ABS malfunction indicator active
- Intermittent loss of wheel speed signal
- ABS system disabled on trailer
- Erratic speedometer reading from trailer axle
Root Causes
- Damaged or contaminated wheel speed sensor tone ring Faulty wheel speed sensor Intermittent wiring or connector issues in sensor circuit Bearing wear causing excessive wheel end play Water or debris intrusion into sensor connector
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Derate Behavior
Power Derate
No
System Interactions
SPN 1250 FMI 10 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.
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OEM System Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 1250 FMI 10 — 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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