SPN 411 FMI 3 — EGR Differential Pressure — Voltage High
What it means: The EGR differential-pressure sensor signal is high/out of range.
How serious / can you keep driving: Caution. Limp to the next safe stop.
Check first: Inspect and clean the EGR pressure sensor tubes — soot packing is extremely common here.
Don't risk it — look up listed providers near you and give them this SPN/FMI when you call.
Listed providers nearest Houston, TX
Closest first. Tell them SPN 411 FMI 3 and what the truck is doing. RoadService.app lists these providers and does not employ them or carry out the repair.
- 0.0 mi away — based in Houston, TX · (832) 377-0578
- 0.0 mi away — based in Houston, TX · (713) 219-9090
- 0.0 mi away — based in Houston, TX · (713) 671-9751
What SPN 411 FMI 3 means
The EGR differential-pressure sensor signal is high/out of range. The ECM may limit EGR flow and stage a derate. Usually it's soot-plugged sensor tubes, a sensor fault, or wiring — not always a failed EGR valve.
How serious is it?
Caution. Limp to the next safe stop.
Most likely causes
- Soot-packed or plugged EGR pressure sensor tubes/ports
- Failed EGR differential-pressure sensor
- Short-to-voltage or chafed signal wiring
- Sticking EGR valve affecting the pressure reading
First moves (roadside)
- Inspect and clean the EGR pressure sensor tubes — soot packing is extremely common here.
- Check the connector and signal wire for a short-to-voltage before replacing the sensor.
- Look for companion EGR valve/position codes that point to the valve itself.
- Verify the reading against actual conditions before condemning parts.
Common misdiagnoses
- Replacing the EGR valve when only the sensor tubes were soot-plugged.
- Condemning the sensor when the harness was shorted high.
- Clearing the code without cleaning the cause of the restriction.
FAQ
The EGR differential-pressure sensor signal is high/out of range. The ECM may limit EGR flow and stage a derate. Usually it's soot-plugged sensor tubes, a sensor fault, or wiring — not always a failed EGR valve.
Caution — Limp to the next safe stop.
The most common cause is: Soot-packed or plugged EGR pressure sensor tubes/ports. Other possibilities include Failed EGR differential-pressure sensor; Short-to-voltage or chafed signal wiring; Sticking EGR valve affecting the pressure reading.
Limp to the next safe stop. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside SPN 411 FMI 3, or share the same subsystem.
- EGR diff pressure high (SPN 411 FMI 0)
- EGR diff pressure — erratic (SPN 411 FMI 2)
- SCR Operator Inducement — Severe Derate Active (SPN 5246 FMI 0)
- Aftertreatment 1 Diesel Particulate Filter Differential Pressure - Data Valid But Above Normal Operating Range, Most Severe Level (DPF severely restricted / plugged) (SPN 3251 FMI 0)
- Aftertreatment 1 Diesel Exhaust Fluid Quality - Data Valid But Below Normal Operating Range, Most Severe Level (DEF quality/concentration incorrect) (SPN 4364 FMI 1)
- DPF Differential Pressure — Data Erratic (SPN 3251 FMI 2)
- DEF Dosing Unit — Not Responding Properly (SPN 3361 FMI 7)
- SCR Conversion Efficiency — Below Threshold (SPN 4364 FMI 18)
Same symptom: Regen problems
Other codes that block a regen or come back as soot load climbing.
- DPF Soot Accumulation Restriction (P2460) · Aftertreatment & Emissions
- DPF inlet temp sensor — voltage high (SPN 3241 FMI 3) · Aftertreatment & Emissions
- DPF outlet temp erratic (SPN 3242 FMI 2) · Aftertreatment & Emissions
- DPF outlet temp sensor — voltage high (SPN 3246 FMI 3) · Aftertreatment & Emissions
- DPF differential pressure — voltage high (SPN 3251 FMI 3) · Aftertreatment & Emissions
- DPF differential pressure — voltage low (SPN 3251 FMI 4) · Aftertreatment & Emissions
Find a mechanic or related guides
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.