AI Diesel Tech

Fault Code Reference

SPN 1088 FMI 2ABS

Front Axle Brake Pressure - Data Erratic/Intermittent

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Connector Pinout — in guided session

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Overview

Fault Code

SPN 1088 / FMI 2

Category

ABS

Derate Risk

No

Regen Inhibit

No

Inducement Risk

No

Component Location: The front axle brake pressure sensor is typically mounted on the brake valve or air line near the front axle assembly.

Common Symptoms

  • ABS warning lamp illuminated
  • Traction control warning lamp active
  • Intermittent or erratic brake pressure readings
  • ABS system disabled or limited functionality
  • Trailer ABS communication fault
  • Brake application feel normal but ABS inactive

Root Causes

  • Faulty front axle brake pressure sensor Damaged or corroded wiring harness to brake pressure sensor Intermittent electrical connection at sensor connector Water or moisture intrusion in sensor or connector Failed ABS control module

Full step-by-step tests, DVOM guidance, and pinout data are available inside the AI Diesel Tech diagnostic session.

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Derate Behavior

Power Derate

No

System Interactions

SPN 1088 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 1088 FMI 2 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.

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