AI Diesel Tech

Fault Code Reference

SPN 1481 FMI 2ABS

ABS Control Unit - Internal Fault - Erratic/Intermittent Data

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Overview

Fault Code

SPN 1481 / FMI 2

Category

ABS

Derate Risk

No

Regen Inhibit

No

Inducement Risk

No

Component Location: ABS control module is typically mounted on the chassis frame rail near the rear axle or inside a frame-mounted electrical enclosure.

Common Symptoms

  • ABS warning lamp illuminated on dash
  • Intermittent loss of ABS function
  • Erratic ABS activation during normal braking
  • ABS system defaults to non-ABS braking mode
  • Trailer ABS communication loss intermittently

Root Causes

  • Faulty ABS control module internal processor Corrupted ABS module software or calibration Intermittent power supply issue to ABS module Internal ABS module memory fault ABS module internal component degradation

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Derate Behavior

Power Derate

No

System Interactions

SPN 1481 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.

Deep-dive diagnostic page: SPN 1481 FMI 2 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.

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