\n
BigRigFaults logo
BigRigFaults
☰
Diagnose
Fault CodesProblemsBrandsEnginesCommunityBrandsEnginesGuideAI DiagnosticsTechnical DataCommunity
Log inRegister
Browse Fault Codes
Jump to
Share ↓
FitmentsMeaningHow it worksImagesDetailed guideOEM/Engine notesLocation hintScan tool checksStep-by-step diagnosticDecision guideMisdiagnosisDerate/inducementChecklistToolsPreventionCommunity discussionsCommunity videosCommunity notesShare
SPN 110 FMI 3Severity: Warning

SPN 110 FMI 3: Engine coolant outlet temperature sensor circuit voltage high

Quick Answer

When SPN 110 FMI 3 sets, the ECM is indicating a fault condition involving the component or system named in the code.

OEM definitions and thresholds can vary, so confirm the exact meaning with service information or a capable diagnostic tool.

Code
SPN 110 FMI 3
Severity
Warning
Applies to
Check OEM application
Can I drive?
A short trip may be possible if the truck is operating normally and there is no stop-engine or critical warning. Diagnose SPN 110 FMI 3 soon and use the live-data and circuit checks below to determine how urgent the fault is.

Common Symptoms

  • MIL or check-engine light may illuminate
  • Engine coolant temperature reading may be implausibly high or unavailable

Likely Causes

  • Coolant temperature sensor signal shorted to voltage
  • Open or damaged sensor ground circuit
  • Engine coolant temperature sensor or connector failure

Quick Diagnostic Checks

Check first
  1. 1Scan for companion codes and record freeze-frame data (if available).
  2. 2Inspect connectors, harness rub points, and pins for corrosion.
  3. 3Check for other active faults that may be upstream causes (communications, sensors, air/fuel issues).
  4. 4After repair, clear codes and confirm the fault stays inactive after a drive cycle.

Common Fixes

  • Inspect the coolant temperature sensor connector and wiring
  • Test supply, ground and signal circuits using the OEM wiring diagram
  • Replace the sensor only after electrical testing confirms sensor failure
Full Technical Guide ↓Share This Fault
Full technical sections↓
FitmentsMeaningHow it worksImagesDetailed guideOEM/Engine notesLocation hintScan tool checksStep-by-step diagnosticDecision guideMisdiagnosisDerate/inducementChecklistToolsPreventionCommunity discussionsCommunity videosCommunity notesShare

What does SPN 110 FMI 3 mean?

Back to top ↑

When SPN 110 FMI 3 sets, the ECM is indicating a fault condition involving the component or system named in the code.

OEM definitions and thresholds can vary, so confirm the exact meaning with service information or a capable diagnostic tool.

Treat repeat faults as ACTIVE and diagnose using live data, wiring checks, and basic inspections before replacing parts.

How this system works (why SPN 110 FMI 3 happens)

Back to top ↑

Most modern fault logic is based on expected versus actual sensor readings, timing windows, circuit checks, and plausibility tests.

A stored code can come from a temporary event, while a repeatable active code gives you a much better diagnostic target.

The goal is to identify whether the failure is electrical, mechanical, sensor-related, or caused by another upstream fault before replacing components.

Detailed guide for SPN 110 FMI 3

Back to top ↑

What SPN 110 FMI 3 means

SPN 110 identifies engine coolant outlet temperature.

FMI 3 indicates that the sensor circuit voltage is above the normal operating range or shorted toward a high source.

This is not an intake-air-temperature fault.

What you may notice

The check-engine or malfunction indicator lamp may illuminate.

The coolant-temperature value shown by diagnostic software may be unrealistic or unavailable.

What to check first

Inspect the engine coolant outlet temperature sensor connector for corrosion, bent terminals or loose connections.

Check the wiring for a short to power or an open ground circuit.

Compare coolant temperature with other temperature sensors when the engine is cold. Large differences can help identify a sensor or circuit fault.

Important

Do not diagnose an overheating condition solely from an FMI 3 electrical fault. Verify the sensor circuit and actual engine temperature before replacing cooling-system components.

Location hint for SPN 110 FMI 3

Back to top ↑

Component location varies by OEM and chassis. Use your engine’s service manual to confirm the sensor/valve location before replacing parts.

Tip: Inspect connectors and harness routing before replacing parts.

Scan tool checks for SPN 110 FMI 3

Back to top ↑
  • Check status: ACTIVE vs INACTIVE / stored and review freeze-frame data when available.
  • Record companion codes and diagnose the earliest or most upstream fault first.
  • Compare live sensor values with expected operating conditions and inspect wiring and connectors.
  • Clear and re-test under similar conditions only after completing the initial inspection.

If your tool can’t run actuator tests, you can still diagnose a lot with careful inspection + repeatability testing.

Step-by-step diagnostic for SPN 110 FMI 3

Back to top ↑
  1. Visual inspection (fast wins). Harness routing, connector pins, hoses/lines (if applicable), and obvious damage.
  2. Check fluid sanity. Not applicable unless your fault is fluid-related. Focus on inspections + repeatability.
  3. Confirm the fault is ACTIVE. Stored-only faults can be old events.
  4. Review live data and circuit values. Use OEM diagnostic software (examples: Cummins INSITE, Detroit DDDL, PACCAR DAVIE4) or a capable heavy-duty scan tool to review the affected signal, commanded/actual values when applicable, and related sensor data.
  5. Verify after repair. Clear codes, road test, confirm it stays inactive.

Decision guide (fast path) for SPN 110 FMI 3

Back to top ↑
  • If the fault is STORED only → inspect, clear, and monitor. If it returns, treat it as active.
  • If ACTIVE → inspect the named component, connector, harness, supply/ground, and live-data plausibility.
  • If multiple codes are present → diagnose the earliest or most upstream code first.

Common misdiagnosis mistakes for SPN 110 FMI 3

Back to top ↑
  • Replacing sensors or components without checking wiring, grounds, connector fitment, and companion codes.
  • Clearing the fault repeatedly without confirming whether it is ACTIVE and repeatable.
  • Missing an upstream fault that is causing the displayed code as a secondary symptom.

Will SPN 110 FMI 3 cause derate or inducement?

Back to top ↑

A warning fault may allow continued operation, but the effect depends on the failed component and any companion faults.

Exact behavior depends on ECM calibration and which companion faults are active.

“Do this first” checklist for SPN 110 FMI 3

Back to top ↑
  • Scan for companion codes and record freeze-frame data (if available).
  • Inspect connectors, harness rub points, and pins for corrosion.
  • Check for other active faults that may be upstream causes (communications, sensors, air/fuel issues).
  • After repair, clear codes and confirm the fault stays inactive after a drive cycle.

Tools needed to diagnose SPN 110 FMI 3

Back to top ↑
  • Basic hand tools + good lighting for inspection
  • Multimeter for connector/power/ground checks (if wiring suspected)
  • OEM diagnostic software (examples: Cummins INSITE, Detroit DDDL, PACCAR DAVIE4) (or equivalent scan tool) for live data and supported diagnostic tests

Prevention tips to avoid repeat SPN 110 FMI 3

Back to top ↑
  • Fix small wiring/connector issues early before they become repeat faults.
  • During service, inspect harness routing and clamp points near heat/vibration.
  • Don’t ignore intermittent faults. “Erratic” usually gets worse.

Video walkthrough for SPN 110 FMI 3

The videos below are embedded using YouTube’s official player. We do not host or claim ownership of this content. Use it as a visual reference and always confirm with diagnostics for your exact truck configuration.

Understanding SPN & FMI Fault Codes (What They Mean)
Channel: Heavy Truck Guides • View in BigRigFaults Media • YouTube source
If a creator disables embedding, the video will stop showing here. That’s normal and it’s their right.
BigRigFaults Community

Community discussions related to SPN 110 FMI 3

Compare symptoms, repairs and real-world experience from drivers, technicians and owner-operators.

Browse Community →
No matching discussion yet for SPN 110 FMI 3.
Start one with the exact code, truck, engine, symptoms and what you already checked.
Still stuck with SPN 110 FMI 3?

Ask the community and include your truck year, make, engine, active codes, symptoms and recent repairs so people can give useful answers instead of performing mechanical astrology.

Ask the Community →

Related fault codes

No related faults found yet. Commonly seen with: SPN 5246, SPN 1569, SPN 4364, SPN 3719.

Mechanic community notes for SPN 110 FMI 3

Back to top ↑

Real-world tips from technicians. Submissions are moderated to keep spam and “my cousin fixed it with duct tape” content out.

No community notes yet. Be the first to add a practical fix that actually works in real life.

Share your fix / advice

Keep it useful: symptoms, what you checked, what fixed it, and whether the code stayed inactive after a drive cycle.

By submitting, you agree it may be edited for clarity and posted publicly after moderation. No spam links.

Share this fault code guide

Help other technicians diagnose SPN 110 FMI 3

WhatsAppFacebookX (Twitter)LinkedInEmailText (SMS)
🔗 https://bigrigfaults.com/faults/spn-110-fmi-3
Back to top ↑