SPN 1071 FMI 2ABS
ABS Axle 1 Left Wheel Speed Sensor - Erratic/Intermittent
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1071 / FMI 2
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The wheel speed sensor is mounted on the axle housing near the brake assembly, positioned close to the tone ring on the axle shaft or hub.
Common Symptoms
- ABS warning lamp illuminated on dash
- ABS system disabled or non-functional
- Intermittent loss of wheel speed signal
- Stability control malfunction warning
- Vehicle may experience reduced braking performance on slippery surfaces
Root Causes
- Damaged or contaminated wheel speed sensor tone ring Faulty wheel speed sensor or internal sensor failure Damaged or corroded wiring harness or connector Excessive wheel bearing play or looseness Debris or metallic contamination buildup on sensor face
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Derate Behavior
Power Derate
No
System Interactions
SPN 1071 FMI 2 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 1071 FMI 2 — 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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