SPN 4077 FMI 3 is the Detroit diesel fault code documented in this hydrocarbon doser flp sensor circuit failed high troubleshooting guide for DD Series (EPA 2007-Current) engines. This 2-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 3 under SPN 4077 — Hydrocarbon Doser FLP Sensor Circuit Failed High |
| Emissions level | All years |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
SPN 4077 FMI 3 troubleshooting steps
- The fuel line pressure (FLP) sensor monitor is always enabled with a 2-second duration and lights the MIL and CEL.
- Check for companion codes; a paired fuel-pressure code points to an open between MCM 120-pin connector pin 104 and the FLP sensor supply.
- Disconnect the FLP sensor, turn the ignition on and connect the diesel diagnostic tool; if the code goes inactive, replace the FLP sensor.
- Measure resistance across the FLP sensor connector pins to locate a short between MCM pins 82 and 111.
- Measure between MCM pin 104 and the sensor signal pin to find a short to power, or repair the open circuit to the sensor.
Applicable truck models and engines
This document applies to Detroit DD Series (EPA 2007-Current) engines and covers the hydrocarbon doser FLP sensor circuit and its MCM wiring. 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 3 manual
Fleet technicians and workshop owners use this guide to trace a circuit-high FLP sensor fault to a short to power, a short between pins or an open circuit. 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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