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SPN 100 FMI 4 — Oil pressure sensor — voltage low

What it means: Oil pressure sensor — voltage low.

How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.

Check first: Unplug — fault should invert

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SeriousLubricationPower derate likely — plan to stop soon

Applies to: Detroit · Navistar · Paccar · Volvo

What SPN 100 FMI 4 means

Oil pressure sensor — voltage low.

How serious is it?

Serious. Power derate likely — plan to stop soon.

Most likely causes

  1. Signal short to ground
  2. Failed sensor
  3. Short ground
  4. Short to ground
  5. Signal to ground

First moves (roadside)

  1. Unplug — fault should invert
  2. Unplug — invert

FAQ

What does SPN 100 FMI 4 mean?

Oil pressure sensor — voltage low.

How serious is SPN 100 FMI 4?

Serious — Power derate likely — plan to stop soon.

What's the most likely cause of SPN 100 FMI 4?

The most common cause is: Signal short to ground. Other possibilities include Failed sensor; Short ground; Short to ground; Signal to ground.

Can I keep driving with SPN 100 FMI 4?

Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.

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Related codes

Codes that commonly appear alongside SPN 100 FMI 4, or share the same subsystem.

Same symptom: Low oil pressure

Other codes a driver sees as an oil-pressure or oil-level warning.

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General diagnostic guidance for heavy-duty diesel engines (Cummins, Detroit, PACCAR, Volvo, Mack). Not a substitute for a scan-tool diagnosis on your specific truck.