Detailed guide for SPN 3610 FMI 4
Back to top ↑Low voltage means the ECM isn’t seeing the real outlet pressure. Hunt for open wires first.
Jump to
Share ↓Level: Warning
SPN 3610 FMI 4: DPF outlet pressure sensor voltage low – open circuit
SPN 3610 FMI 4: DPF outlet pressure sensor voltage low – open circuit. Symptoms (3), causes (3), and fixes (3). What to check first to prevent derate and downtime.
| Code | SPN 3610 FMI 4 |
|---|---|
| Severity | Warning |
| Applies to | Varies by OEM configuration (confirm your exact calibration) |
| Can I drive? | Usually yes for a short distance, but fix it soon. Warning faults like SPN 3610 FMI 4 commonly escalate into torque derate if ignored. The scan-tool checks below help determine urgency. |
Symptoms
3
Likely causes
3
Fixes
3
Advertisement
Ad - helps keep this content free
What does SPN 3610 FMI 4 mean?
Back to top ↑When SPN 3610 FMI 4 sets, the ECM is indicating a fault condition that affects performance, protection strategy, or emissions (depending on calibration).
OEM definitions can vary slightly, so confirm your exact meaning with your service manual or diagnostic tool.
Treat repeat faults as ACTIVE and diagnose using a scan tool and basic inspections before replacing parts.
How this system works (why SPN 3610 FMI 4 happens)
Back to top ↑Most modern fault logic is based on expected vs actual sensor readings, timing windows, and plausibility checks.
A single event might store a code, but repeated events across drive cycles are what typically trigger warnings, derate strategies, or inducement (emissions systems).
Your goal is to identify the failure mode (electrical, mechanical, sensor drift, or upstream cause) rather than “parts cannon” replacement.
Location hint for SPN 3610 FMI 4
Back to top ↑The DPF differential pressure sensor is usually mounted on/near the firewall or aftertreatment bracket. It connects to the exhaust via two small pressure tubes (pre- and post-DPF). Check the tubes for soot blockage, cracks, water intrusion, and heat damage.
Tip: Soot blockage or water in the DP tubes is a very common cause of erratic differential pressure readings.
Scan tool checks for SPN 3610 FMI 4
Back to top ↑- Check status: ACTIVE vs INACTIVE / stored. If it’s not active, review last occurrence conditions (freeze-frame if available).
- Record companion codes (regen inhibited, soot load, exhaust leak, sensor supply voltage). Fix upstream causes first.
- Inspect DP sensor tubes/hoses for soot blockage, cracks, melted sections, and water intrusion.
- Compare DP readings at idle vs under load. Erratic signals often point to wiring, sensor, or blocked tubes.
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 3610 FMI 4
Back to top ↑- Visual inspection (fast wins). Sensor connector/wiring, DP sensor tubes/hoses, soot blockage, water intrusion, exhaust leaks.
- Check fluid sanity. Not applicable unless your fault is fluid-related. Focus on inspections + repeatability.
- Confirm the fault is ACTIVE. Stored-only faults can be old events.
- 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.
- Verify after repair. Clear codes, road test, confirm it stays inactive.
Decision guide (fast path) for SPN 3610 FMI 4
Back to top ↑- If the fault is STORED only → inspect DP tubes/hoses + wiring, clear, and monitor. If it returns, treat it as active.
- If ACTIVE → check tubes for blockage/water → then verify wiring/connector → then evaluate sensor readings plausibility.
- If exhaust leak codes exist → fix leaks first. Leaks can skew delta-P readings.
Common misdiagnosis mistakes for SPN 3610 FMI 4
Back to top ↑- 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.
Will SPN 3610 FMI 4 cause derate or inducement?
Back to top ↑Warning aftertreatment faults often start as an emissions warning, then progress to torque derate if the fault remains active over multiple drive cycles. If ignored, many platforms can eventually enter inducement and severe speed limiting.
Exact behavior depends on ECM calibration and which companion faults are active.
“Do this first” checklist for SPN 3610 FMI 4
Back to top ↑- Scan for companion codes (regen inhibited, soot load, exhaust leak, sensor supply voltage).
- Inspect DP sensor tubes/hoses for soot blockage, cracks, melted spots, and water intrusion.
- Check wiring/connector pin fitment at the DP sensor (chafing and loose pins are common).
- Verify exhaust system integrity (leaks before/after DPF can skew delta-P readings).
- Clear codes and perform a controlled drive/regen to confirm readings are stable.
Tools needed to diagnose SPN 3610 FMI 4
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 actuator tests and live data
Prevention tips to avoid repeat SPN 3610 FMI 4
Back to top ↑- Inspect DP sensor tubes/hoses during service. Soot blockage builds over time.
- Fix exhaust leaks early. They can skew DP readings and regen behavior.
- Avoid excessive idling when possible (regen systems hate it).
- Watch for water intrusion in sensor lines after heavy rain/steam cleaning.
What to check first for SPN 3610 FMI 4
- Inspect connectors and harness near the affected component for corrosion, rubbing, or loose pins.
- Inspect DP sensor tubes/hoses for blockage, water, or heat damage.
- Check for other active faults that may be upstream causes (communications, sensors, air/fuel issues).
If the fault repeats after clearing, diagnose it as ACTIVE. Many faults escalate into derate when ignored.
Related fault codes
No related faults found yet. Commonly seen with: SPN 5246, SPN 1569, SPN 4364, SPN 3719.
Mechanic community notes for SPN 3610 FMI 4
Back to top ↑Real-world tips from technicians. Submissions are moderated to keep spam and “my cousin fixed it with duct tape” content out.
Share your fix / advice
Keep it useful: symptoms, what you checked, what fixed it, and whether the code stayed inactive after a drive cycle.