SPN 1072 FMI 5 is the Detroit DD Series fault-code troubleshooting sheet that documents a Jake Brake Stage 1 circuit failed open condition on the Motor Control Module engine platform. This 2-page reference reproduces the fault-code identification and the factory decision tree so a technician can diagnose the concern before replacing parts.
Official document details — SPN 1072 FMI
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-Current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | FMI 5 under SPN 1072 (ALL YEARS) |
| Source | Detroit fault-code literature via TruckFaultCodes.com, © 2017 |
| Pages | 2 |
| Format | |
| Language | English |
SPN 1072 FMI 5 fault description
This two-page procedure isolates an open in the stage-1 engine-brake circuit. The technician disconnects the front connector of the two-piece fuel injector wiring harness and measures resistance between pins 13 and 14 on the valve-cover side, expecting 9 to 12 ohms. Based on the result, it directs a key-on voltage check at pin 14 to ground, then removal of the rocker cover to reach the front Jake Brake solenoid, where resistance is measured across the solenoid, expecting 9 to 11 ohms. The outcome points to either the two-piece harness or the front Jake Brake solenoid.
The SPN 1072 FMI 5 sheet identifies the following likely causes and check points:
- Open or out-of-range resistance in the two-piece fuel injector wiring harness
- Low supply voltage to pin 14 of the valve-cover harness
- Failed front Jake Brake solenoid
Document table of contents
- Fault code identification
- Valve-cover harness resistance check
- Key-on voltage measurement
- Front Jake Brake solenoid test
Service tools referenced
- J-48671-10 test adapter
Applicable truck models
This troubleshooting sheet applies to Detroit DD Series engines built from EPA 2007 to current that use the Motor Control Module (MCM) and Common Powertrain Controller architecture. Confirm the engine’s emissions family and calibration against the manufacturer’s official documentation at the Detroit engine website before repairs.
Who needs this SPN 1072 FMI 5 manual
Heavy-duty diesel technicians, fleet shops and mobile mechanics who retrieve this code on a Detroit DD engine need this manual to follow the factory decision tree instead of guessing. It is written for anyone using DDDL or an equivalent diesel diagnostic tool who wants the exact test values before condemning a component.
The full 2-page PDF of this procedure is available in the DiagTechPro manuals library; a free account is required to download.
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