SPN 1072 FMI 4 is the Detroit DD Series fault-code troubleshooting sheet that documents a Jake Brake Stage 1 circuit failed low condition, illuminating the MIL and CEL lamps 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 4 under SPN 1072 (ALL YEARS) |
| Source | Detroit fault-code literature via TruckFaultCodes.com, © 2017 |
| Pages | 2 |
| Format | |
| Language | English |
SPN 1072 FMI 4 fault description
This two-page sheet isolates a short to ground in the stage-1 engine-brake circuit. The technician disconnects the front fuel injector valve-cover harness and measures resistance from pin 13 to ground, expecting more than 15 ohms; a lower reading identifies a short toward pin 66 of the Motor Control Module (MCM) 120-pin connector. If that passes, the rocker cover is removed and resistance is measured from a Jake Brake solenoid terminal to ground, resolving the fault to either the front Jake Brake solenoid or a short between pins 13 and 14 of the valve-cover harness.
The SPN 1072 FMI 4 sheet identifies the following likely causes and check points:
- Short to ground between pin 13 of the harness and pin 66 of the MCM
- Failed front Jake Brake solenoid
- Short between pins 13 and 14 of the valve-cover harness
Document table of contents
- Description and monitored conditions
- Harness resistance-to-ground check
- Rocker cover removal
- Front Jake Brake solenoid measurement
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 4 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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