SPN 1348 FMI 31ABS
ABS System - 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 1348 / FMI 31
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: ABS components are distributed across the vehicle with wheel speed sensors at each axle, modulator valve typically mounted on frame rail, and ECU near battery box or chassis.
Common Symptoms
- ABS warning light illuminated on dash
- ABS system non-functional or disabled
- Loss of traction control functionality
- Warning message on instrument cluster
- No diagnostic lamp illumination in some cases
Root Causes
- ABS wheel speed sensor fault or signal degradation ABS modulator valve malfunction or air contamination Wiring harness damage or connector corrosion in ABS circuit ABS ECU internal fault or software issue Tone ring damage or excessive air gap at sensor
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Derate Behavior
Power Derate
No
System Interactions
SPN 1348 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 1348 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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