This Detroit barometric pressure high reference documents fault code SPN 108/FMI 3 (Barometric Pressure (BP) Sensor Circuit Failed High) for Detroit DD-series engines with the barometric sensor in the MCM. 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 barometric pressure high troubleshooting overview
This sheet documents a barometric pressure circuit that has failed high. It lists the always-enabled monitor, the two-second duration, the MIL and CEL lamps and a 25% derate. With the code present the prescribed repair is replacing the Motor Control Module (MCM), which contains the barometric sensor. 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 with the barometric sensor in the MCM |
| System / group | DTCs — barometric pressure sensor circuit |
| Fault code | SPN 108/FMI 3 |
| Source publication | TruckFaultCodes.com (© 2017) |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification — SPN 108/FMI 3
- Description — barometric pressure circuit failed high
- Enabling conditions, 2-second duration, MIL and CEL lamps
- Engine reaction — 25% derate
- Corrective action — replace the Motor Control Module
Applicable truck models
It applies to Detroit DD-series engines whose barometric sensor is integral to the Motor Control Module. 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 barometric pressure high manual
Mechanics who need to confirm the circuit fault direction before condemning the MCM. 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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