SPN 1485 FMI 5ABS
ABS Warning Lamp - Current Below Normal/Open Circuit
Scan Tool — in guided session
DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1485 / FMI 5
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: ABS warning lamp is located in the instrument cluster, with wiring routed from the Bendix ABS module to the dash panel.
Common Symptoms
- ABS warning lamp inoperative or dim
- ABS warning lamp does not illuminate with key on
- No bulb check on startup
- ABS lamp fault code active
- ABS system may still function normally
Root Causes
- Open circuit in ABS warning lamp wiring harness Faulty ABS warning lamp bulb or LED Corroded or damaged instrument cluster connector Failed ABS controller output circuit Damaged wiring between ABS module and instrument cluster
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Derate Behavior
Power Derate
No
System Interactions
SPN 1485 FMI 5 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 1485 FMI 5 — 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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