SPN 2791 FMI 4 is the Detroit DD Series diagnostic trouble code for egr valve circuit failed low, and this page documents the 1-page fault-code PDF for it. It gives mechanics the monitored conditions, the step-by-step troubleshooting sequence and the EGR valve circuit checks needed to diagnose the fault. The full document is a Detroit fault code sheet built from Detroit Power Service Literature references.
Official document details
| Brand | Detroit (Detroit Diesel / DTNA) |
| Model coverage | DD13, DD15 and DD16 |
| System / Group | DD Series (EPA 2007-Current) / DTCs — EGR valve circuit |
| Suspect Parameter Number | 2791 |
| Failure Mode Identifier | 4 |
| Fault description | EGR Valve Circuit Failed Low |
| Year / Emissions | EPA07, EPA10 and GHG14 (all years) |
| Pages | 1 |
| File size | 0.22 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code header: SPN and FMI identification
- Troubleshooting steps
- Component removal references (Detroit Power Service Literature)
- Verification and clearing the code
SPN 2791 FMI 4 diagnostic overview
This code identifies a circuit-failed-low condition on the EGR valve. After ruling out SPN 3598/FMI 4, resistance is measured from EGR valve pin 1 to ground to decide between repairing a short and replacing the valve on DD13, DD15 or DD16 engines. Reading SPN 2791 FMI 4 correctly stops parts being replaced before the wiring and mechanical checks are done.
Applicable truck models
This Detroit DD Series fault code sheet applies to the DD13, DD15 and DD16 engines in the DD Series (EPA 2007-Current) family, covering EPA07, EPA10 and GHG14 (all years) configurations, and the same code also appears in Detroit Series 60 DDEC VI listings. Component removals point to Detroit Power Service Literature, and unresolved cases route to the Detroit Customer Support Center at 800-445-1980. Verify engine and emissions level against your build on the official Detroit brand site before ordering parts.
Who needs this 2791 FMI 4 manual
Heavy-duty diesel technicians, fleet workshops and owner-operators running Detroit DD engines use this EGR valve circuit sheet with a diesel diagnostic tool to work the fault methodically instead of guessing.
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