SPN 3515 FMI 14ABS
ABS ECU Internal Fault - Special Instructions
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 3515 / FMI 14
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The ABS ECU is typically mounted on the vehicle frame rail or firewall near the air brake system components.
Common Symptoms
- ABS warning light illuminated on dash
- ABS system disabled or inactive
- Loss of traction control functionality
- Diagnostic trouble code stored in ABS ECU memory
Root Causes
- ABS ECU internal software corruption or calibration error ABS ECU hardware component failure Power supply voltage interruption or spike to ABS ECU Water intrusion or corrosion inside ABS ECU ECU memory fault or configuration mismatch
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Derate Behavior
Power Derate
No
System Interactions
SPN 3515 FMI 14 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 3515 FMI 14 — 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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