AI Diesel Tech

Fault Code Reference

SPN 95 FMI 0FuelHigh

Engine Fuel Filter Differential Pressure — High

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DVOM Testing — in guided session

Connector Pinout — in guided session

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Overview

Fault Code

SPN 95 / FMI 0

Category

Fuel

Fault Type

sensor

FMI Category

performance

Severity

High

Derate Risk

Yes

Regen Inhibit

No

Inducement Risk

No

Component Location: Fuel filter — on engine or frame rail; differential pressure sensor — on filter housing

Common Symptoms

  • Fuel filter restriction warning
  • Low fuel delivery pressure
  • Engine derate
  • Hard start

Root Causes

  • Fuel filter severely restricted
  • Fuel contamination
  • Fuel filter change interval exceeded
  • Wax in fuel in cold weather

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Derate Behavior

Power Derate

Yes

Mileage / Regen Notes

Fuel filter restriction common at 15k–25k miles.

System Interactions

SPN 95 FMI 0 interacts with the following systems and may trigger cascading faults if not resolved promptly.

TSB Reference: Cummins TSB 4021687 — Fuel Filter Restriction Diagnosis

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.

OEM Notes

Cummins

X15: Replace fuel filter every 15k–25k miles.

Detroit

DD15: Check fuel supplier for contamination.

PACCAR

MX-13: Check fuel tank for debris.

Deep-dive diagnostic page: SPN 95 FMI 0 — Full FSM Sequence & Repair Steps — includes wiring notes, sensor specs, and gated repair procedures.

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