This FCP sensor circuit low sheet documents Detroit SPN 3480 FMI 4, a low reading on the fuel compensation pressure sensor branch. It uses companion codes and resistance checks to place a short or open in the harness. Follow it before replacing the sensor.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | DD Series (EPA 2007-Current); also filed under Series 60 (DDEC VI – EPA 2007) |
| System / Group | DTCs — Fuel Compensation Pressure (FCP) Sensor Circuit Failed Low |
| Fault code | SPN 3480 / FMI 4 |
| Source | www.TruckFaultCodes.com (© 2017) |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
FCP sensor circuit low diagnostic guide
The technician reads multiple codes: SPN 100 FMI 4 and SPN 4077 FMI 4 alongside point to a short to power at MCM pin 104. If only the one code is present, the sensor connector is inspected, the MCM 120-pin connector is disconnected and resistance from the 5-volt supply and signal branches to ground is measured against a 10 kilo-ohm threshold. The readings separate a short to ground from an open at MCM pin 82, and a shorted signal-to-ground wire at pin 111, before the sensor is replaced and the repair verified.
Document table of contents
- Fault code identification: SPN 3480, FMI 4
- Description, monitored parameter and enabling conditions
- Companion code checks (SPN 100 and SPN 4077)
- FCP sensor and MCM pin resistance checks
- Sensor replacement and verification
Applicable truck models
This procedure applies to Detroit DD Series engines built for EPA 2007 and later, covering all model years (EPA07, EPA10 and GHG14) as printed on the document cover, and the identical SPN/FMI sheet is also filed under Detroit Series 60 (DDEC VI, EPA 2007). Confirm the emissions platform on your truck and cross-check the connector and pin numbers against the official Detroit engine support site before making any repair.
Who needs this FCP sensor circuit low manual
A diesel technician on any Detroit DD model year facing a low compensation pressure signal uses this sheet to read companion codes and resistances so a harness fault is not mistaken for a bad sensor.
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