SPN 2659 FMI 0 — EGR 1 Differential Pressure - Data Valid But Above Normal Operating Range (EGR flow/differential pressure too high)
What it means: EGR 1 Differential Pressure - Data Valid But Above Normal Operating Range (EGR flow/differential pressure too high).
How serious / can you keep driving: Serious. Power derate likely — plan to stop soon.
Check first: 1) Check the EGR differential pressure sensor and its two small hoses at the EGR cooler outlet for soot blockage or cracking. 2) Check engine coolant level and the coolant recovery tank for unexplained loss - a classic symptom of a cracked ISX15 EGR cooler. 3) Data-log EGR valve commanded versus actual position with INSITE - a sticking valve will report false flow numbers
Don't risk it — look up listed providers near you and give them this SPN/FMI when you call.
Listed providers nearest Baltimore, MD
Closest first. Tell them SPN 2659 FMI 0 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 Baltimore, MD · (443) 680-6789
- 0.0 mi away — based in Baltimore, MD · (410) 544-3888
- 24 hour Mobile Diesel Truck Engine Repair DEF Repairs On Site Services Road Service Laptop Diagnostic Tractors & Dump Truck☎ Call0.0 mi away — based in Baltimore, MD · (443) 591-3631
Applies to: Cummins Isx15 · Freightliner Cascadia · International ProStar (ISX15 2013-2019) · Kenworth T680 · Peterbilt 579
What SPN 2659 FMI 0 means
EGR 1 Differential Pressure - Data Valid But Above Normal Operating Range (EGR flow/differential pressure too high).
How serious is it?
Serious. Power derate likely — plan to stop soon.
Most likely causes
- EGR cooler partially plugged with soot or cracked internally
- restricting/altering normal EGR gas flow
- EGR differential pressure sensor or its hoses soot-clogged giving a false high reading
- EGR valve sticking and reporting inaccurate position
- coolant intrusion into the EGR cooler from a cracked core
- exhaust restriction downstream skewing pressure differential
First moves (roadside)
- 1) Check the EGR differential pressure sensor and its two small hoses at the EGR cooler outlet for soot blockage or cracking. 2) Check engine coolant level and the coolant recovery tank for unexplained loss - a classic symptom of a cracked ISX15 EGR cooler. 3) Data-log EGR valve commanded versus actual position with INSITE - a sticking valve will report false flow numbers
FAQ
EGR 1 Differential Pressure - Data Valid But Above Normal Operating Range (EGR flow/differential pressure too high).
Serious — Power derate likely — plan to stop soon.
The most common cause is: EGR cooler partially plugged with soot or cracked internally. Other possibilities include restricting/altering normal EGR gas flow; EGR differential pressure sensor or its hoses soot-clogged giving a false high reading; EGR valve sticking and reporting inaccurate position; coolant intrusion into the EGR cooler from a cracked core; exhaust restriction downstream skewing pressure differential.
Power derate likely — plan to stop soon. When in doubt, get a qualified mobile diesel tech on the truck before continuing.
Related codes
Codes that commonly appear alongside SPN 2659 FMI 0, or share the same subsystem.
- 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)
- DEF Quality — Out of Spec (SPN 4094 FMI 31)
- EGR Temperature — Too High (SPN 412 FMI 0)
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.