SPN 1072 FMI 3 is the Detroit DD Series fault-code troubleshooting sheet that documents a Jake Brake Stage 1 circuit failed high condition on the Motor Control Module engine platform. This 1-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
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-Current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Fault code | FMI 3 under SPN 1072 (ALL YEARS) |
| Source | Detroit fault-code literature via TruckFaultCodes.com, © 2017 |
| Pages | 1 |
| Format | |
| Language | English |
SPN 1072 FMI 3 fault description
This single-page sheet gives the direct corrective action for a stage-1 engine-brake circuit that has failed high. The repair is to fix the short to battery power between pin 1 on the Jake Brake solenoid and pin 66 on the Motor Control Module (MCM) 120-pin connector. As with other failed-high engine-brake circuits, the failure mode indicates unwanted voltage on the control wire, so the sheet serves as a concise wiring-repair reference for technicians who have already confirmed the code with a diesel diagnostic tool and need the exact pins to inspect.
The SPN 1072 FMI 3 sheet identifies the following likely causes and check points:
- Short to battery power on the stage-1 Jake Brake circuit
- Voltage present between pin 1 of the solenoid and pin 66 of the MCM
Document table of contents
- Fault code identification
- Circuit short-to-power repair between the solenoid and the MCM
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 3 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 1-page PDF of this procedure is available in the DiagTechPro manuals library; a free account is required to download.
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