AI Diesel Tech

Fault Code Reference

SPN 3512 FMI 4ABS

Yaw Rate Sensor - Voltage Below Normal

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DVOM Testing — in guided session

Connector Pinout — in guided session

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Overview

Fault Code

SPN 3512 / FMI 4

Category

ABS

Derate Risk

No

Regen Inhibit

No

Inducement Risk

No

Component Location: Yaw rate sensor is typically mounted on the vehicle frame near the center of the wheelbase, often close to the ABS ECU.

Common Symptoms

  • ABS warning lamp illuminated
  • Stability control system disabled or lamp illuminated
  • Roll stability control inactive
  • Traction control disabled
  • Electronic stability program (ESP) malfunction light on
  • No derate or limp mode from this fault alone

Root Causes

  • Faulty yaw rate sensor internal failure Damaged or corroded wiring harness to yaw rate sensor Poor ground connection at sensor mounting location Water intrusion in sensor connector ECU internal fault or power supply issue

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 3512 FMI 4 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 3512 FMI 4 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.

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