SPN 3719 FMI 16: DPF soot load too high – regen required / forced regen likely. Symptoms (3), causes (3), and fixes (3). What to check first to prevent derate and downtime. Critical: don’t ignore.
| Code | SPN 3719 FMI 16 |
|---|---|
| Severity | Critical |
| Applies to | Varies by OEM configuration (confirm your exact calibration) |
| Can I drive? | Not recommended. SPN 3719 FMI 16 is marked critical and may escalate into derate or shutdown. Diagnose immediately and confirm whether the fault is ACTIVE vs stored (steps below). |
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When SPN 3719 FMI 16 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.
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.
This is the classic “I’ve been idling all week and now it hates me” code. The truck needs a full regen, and it needs you to stop killing the regen halfway through.\n\nIf it comes back quickly, you’ve got a root cause (sensor data, exhaust leak, or restriction).
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.
If your tool can’t run actuator tests, you can still diagnose a lot with careful inspection + repeatability testing.
Critical aftertreatment faults can trigger rapid derate depending on calibration. Some trucks reduce torque quickly and may progress to severe speed limiting if the fault stays active.
Exact behavior depends on ECM calibration and which companion faults are active.
If the fault repeats after clearing, diagnose it as ACTIVE. Many faults escalate into derate when ignored.
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.
Mechanic community notes for SPN 3719 FMI 16
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