SPN 1077 FMI 10ABS
ABS Modulator Valve - Axle 1 Left - Abnormal Rate of Change
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DVOM Testing — in guided session
Connector Pinout — in guided session
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Overview
Fault Code
SPN 1077 / FMI 10
Category
ABS
Derate Risk
No
Regen Inhibit
No
Inducement Risk
No
Component Location: The ABS modulator valve assembly is typically mounted on the vehicle frame near the front axle brake components or integrated into the Bendix ABS control unit.
Common Symptoms
- ABS warning lamp illuminated on dash
- ABS system disabled or inactive
- Unusual brake pedal pulsation during normal braking
- ABS activation feels abnormal or delayed
- Reduced braking performance in low traction conditions
Root Causes
- Faulty ABS modulator valve solenoid on axle 1 left Contaminated brake fluid affecting valve operation Internal ABS modulator valve sticking or binding Corroded or damaged ABS modulator valve connector ECU detecting rapid pressure fluctuations from modulator valve
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Derate Behavior
Power Derate
No
System Interactions
SPN 1077 FMI 10 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 1077 FMI 10 — 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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