SPN 110 FMI 2: SPN 110 FMI 2 - Engine Control

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.

• Check status: ACTIVE vs INACTIVE / stored. If it’s not active, look at last occurrence conditions (freeze-frame if available).
• Record companion codes. Fixing the “first” code often makes others disappear.
• Clear and re-test under similar conditions. If it returns quickly, you have a repeatable fault (good for diagnosis).

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

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. Run actuator tests (if supported). Use OEM diagnostic software (examples: Cummins INSITE, Detroit DDDL, PACCAR DAVIE4) (or a capable J1939 tool) to command tests when available.
5. Verify after repair. Clear codes, road test, confirm it stays inactive.

• If the fault is STORED only → inspect, clear, and monitor. If it returns, treat it as active.
• If ACTIVE → check connector/harness first → then confirm sensor values and plausibility → then consider component testing.
• If you have multiple codes → diagnose the earliest/most upstream code first.

• Replacing sensors without checking wiring, grounds, and connector pin fitment.
• Clearing codes repeatedly without confirming whether the fault is ACTIVE and repeatable.
• Missing companion codes that point to the real upstream problem.

Info-level faults usually don’t derate immediately, but repeated faults can indicate a developing issue that later becomes a warning/critical condition.

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

• Scan for companion/derate 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.

• 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 actuator tests and live data

• 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.

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