The SPN 94 FMI 1 document is a Detroit DD Series diagnostic trouble code guide covering the fuel pressure in the low pressure circuit too low condition and its step-by-step troubleshooting. This 2-page PDF is compiled from the TruckFaultCodes.com Detroit fault codes reference (© 2017) for the DD Series (EPA 2007-Current) / DTCs set. It is written for workshop diagnostics rather than general reading.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD Series (EPA 2007-Current); Detroit Series 60 (DDEC VI – EPA 2007) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Diagnostic trouble code | SPN 94/FMI 1 — Fuel Pressure In Low Pressure Circuit Too Low |
| Publication no. | Not stated (TruckFaultCodes.com DTC reference) |
| Year / Revision | © 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
SPN 94 FMI 1 document sections
- Fault code identification: SPN 94/FMI 1 — low pressure circuit fuel pressure too low
- Disconnecting the low pressure pump output (LPPO) fuel pressure sensor
- Voltage measurements between pins 2 and 3 (4.75 to 5 volts)
- Wiring repairs to MCM2.1 120-pin connector pins 102, 117 and 113
- Resistance check and LPPO sensor replacement
Applicable truck models covered
The SPN 94 FMI 1 fault applies to the models below. This procedure covers Detroit DD Series (EPA 2007-Current); Detroit Series 60 (DDEC VI – EPA 2007) engines equipped with the Motor Control Module. The steps reference the systems named in the extract only — LPPO fuel pressure sensor components, harness connectors and, where present, the MCM 120-pin connector. Confirm engine and emissions configuration against the vehicle build before ordering parts; verify current procedures on the Detroit Diesel official site.
Who needs this 94 FMI 1 manual
This reference suits drivability technicians and workshop owners tracing low-side and compensation fuel pressure sensor circuits. Every troubleshooting step and decision branch from the original PDF is preserved so the on-vehicle diagnosis can be followed in sequence. Use it alongside a Detroit-compatible scan tool such as DDDL or DDRS.
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