SPN 1480 FMI 31ABS
ABS System Active - Condition Exists
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1480 / FMI 31
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The ABS ECU is typically mounted on the vehicle frame rail near the air supply system with wheel speed sensors at each wheel end.
Common Symptoms
- ABS warning lamp illuminated on dash
- ABS system actively modulating brake pressure
- Wheel speed sensor signal variation detected
- Intermittent or continuous ABS activation during braking
- Traction control or stability control intervention active
Root Causes
- ABS controller detecting wheel speed sensor discrepancy during normal operation Wheel speed sensor signal intermittent or erratic Tone ring damage or debris accumulation affecting sensor reading ABS valve solenoid actively modulating during brake application Low system air pressure triggering ABS intervention
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Derate Behavior
Power Derate
No
System Interactions
SPN 1480 FMI 31 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
ASE Training Resources
Diagnostic Engine v7.0
Related Diagnostic Articles
Deep-dive diagnostic page: SPN 1480 FMI 31 — 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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