SPN 1245 FMI 7ABS
Wheel Speed Sensor - Rear Left - Mechanical System Not Responding
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1245 / FMI 7
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The rear left wheel speed sensor is mounted on the axle housing adjacent to the tone ring on the rear left wheel hub assembly.
Common Symptoms
- ABS warning lamp illuminated on dashboard
- ABS system disabled or inactive
- Traction control system not functioning
- Stability control warning light active
Root Causes
- Damaged or missing tone ring teeth Excessive wheel bearing play or bearing failure Misaligned or displaced wheel speed sensor Debris or buildup between sensor tip and tone ring Worn or damaged tone ring
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Derate Behavior
Power Derate
No
System Interactions
SPN 1245 FMI 7 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
ASE Training Resources
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Related Diagnostic Articles
Deep-dive diagnostic page: SPN 1245 FMI 7 — 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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