This Detroit oil pressure fault reference documents fault code SPN 100/FMI 18 (Very Low Oil Pressure) for Detroit DD-series engines across all model years. It reproduces the original TruckFaultCodes.com fault tree, from the first check through the final repair, so the code can be confirmed and worked in the exact order the factory intended. Each step lists the measured value or check and the pass or fail branch that follows, matching the layout used in the source document.
Detroit oil pressure fault troubleshooting overview
This all-years tree clears companion codes SPN 100/FMI 3 and FMI 4, then checks whether oil pressure is fluctuating. It steps through oil level, the oil gauge, the pump suction pipe, drive and driven gears and the pressure-relief valve, and finishes by checking for fuel in the oil. Cases with oil above maximum route to the Detroit Customer Support Center. Follow the checks in sequence and verify the repair before clearing the code and releasing the vehicle.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD-series engines across all model years |
| System / group | DTCs — engine oil pressure |
| Fault code | SPN 100/FMI 18 |
| Source publication | TruckFaultCodes.com (© 2017) |
| Pages | 2 |
| File size | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification — SPN 100/FMI 18
- Companion-code checks (SPN 100/FMI 3 and FMI 4)
- Oil-pressure fluctuation check
- Oil level, gauge, pump and relief-valve checks
- Fuel-in-oil check; contact the Customer Support Center
Applicable truck models
It applies to Detroit DD-series engines across all model years. Always cross-check the reading against any companion codes before condemning a component. For the official product and service literature, visit the Detroit Diesel website.
Who needs this Detroit oil pressure fault manual
Mechanics who need the mechanical decision path for a very-low-oil-pressure DTC. It is written for shop use as a quick, printable reference to keep beside a diesel diagnostic tool during the job.
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