SPN 704 FMI 3 is the Detroit fault code documented in this 2-page reference for the DD Series (EPA 2007-Current) engines. The sheet identifies the code as the High Exhaust System Temperature Lamp circuit and reports a short to power or open circuit on pin 7 of the CPC #4 connector. It is published for use with the diesel diagnostic tool and cites TruckFaultCodes.com, Copyright 2017, as its source.
SPN 704 FMI 3 document details
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-Current); shared with Series 60 (DDEC VI – EPA 2007) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | SPN 704 with FMI 3 (High Exhaust System Temperature Lamp) |
| Fault condition | Short to power or open circuit on pin 7 of the CPC #4 connector |
| Source | TruckFaultCodes.com, Copyright 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
What this fault code covers
The reference confirms the code as the High Exhaust System Temperature Lamp circuit showing a short to power or open circuit on pin 7 of the CPC #4 connector. It carries the standard advisory that the Common Powertrain Controller (CPC) digital outputs share the same SPN as some Motor Control Module (MCM) faults, and that the diesel diagnostic tool separates the MCM from the CPC when diagnosing. For wiring detail it refers the technician to Original Equipment Manufacturer (OEM) literature.
Troubleshooting steps included
The page also includes a numbered troubleshooting sequence: turn the ignition on, connect the diesel diagnostic tool, confirm the PGR035 digital-output parameters, then repair the fault on the affected pin per OEM literature.
Applicable Detroit truck models
This page applies to Detroit DD Series (EPA 2007-Current) engines, and, where the fault is shared across platforms, Series 60 (DDEC VI – EPA 2007) engines. The same pin and connector references hold across engines built around the CPC and MCM architecture. Confirm the wiring layout against the manufacturer’s own documentation before opening the harness; official engine information is published by Detroit (Demand Detroit).
Who needs this SPN 704 FMI 3 manual
Fleet technicians, mobile diesel mechanics and workshop owners diagnosing a lit dashboard warning or a logged High Exhaust System Temperature Lamp code on a Detroit engine will use this sheet to confirm the circuit, pin and connector before touching the wiring, and to decide whether the CPC or MCM raised the fault.
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