SPN 4077 FMI 1 is the Detroit diesel fault code documented in this abnormal hydrocarbon doser fuel line pressure troubleshooting guide for DD Series (EPA 2007-Current) engines. This 3-page PDF explains the monitored condition, the enabling parameters and the step-by-step checks a technician follows to confirm and repair the code. It is part of the Detroit DD Series diagnostic trouble code (DTC) library and follows the standard monitored-parameter, enabling-conditions and troubleshooting-step layout used across the Detroit fault-code set.
Official document details
| Brand | Detroit (Detroit Diesel) |
|---|---|
| Model coverage | DD Series (EPA 2007-Current); cross-referenced for Series 60 (DDEC VI – EPA 2007) |
| System / group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | FMI 1 under SPN 4077 — Abnormal Hydrocarbon Doser Fuel Line Pressure |
| Emissions level | All years |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
SPN 4077 FMI 1 troubleshooting steps
- Shut off the engine, apply the parking brake, chock the wheels and complete the applicable safety steps.
- Repair any fuel-system faults first, then check for and repair companion codes SPN 4077 FMI 14 and the related SPN 3480 codes before continuing.
- Visually inspect the HC doser block assembly and the fuel doser injector valve fuel lines for external leaks; one drop of fuel can cause a failure.
- Start the engine and perform a parked regeneration with the diesel diagnostic tool.
- If the code becomes active during regeneration, retain the regen log file and contact the Detroit Customer Support Center at 800-445-1980; otherwise clear the codes and release the vehicle.
Applicable truck models and engines
This document applies to Detroit DD Series (EPA 2007-Current) engines and covers abnormal hydrocarbon doser fuel line pressure during regeneration. The procedure is published in Detroit Power Service Literature and drawn from the Detroit diesel fault-code set; always confirm the latest revision through the official Detroit engine support site.
Who needs this SPN 4077 FMI 1 manual
Fleet technicians and workshop owners use this guide to work through companion doser codes and a leak inspection before escalating to Detroit support. Reading the full procedure before touching the harness keeps the diagnosis on the documented path and avoids replacing good parts.
The full PDF is available in the DiagTechPro manuals library, where a free account is required to download.
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