The Detroit compressor inlet sensor troubleshooting sheet documents Detroit fault code SPN 1172 FMI 4, which sets when the compressor inlet (TCI) temperature sensor or circuit failed low. This 1-page PDF belongs to the Detroit DD Series (EPA 2007-Current) DTC library and guides a technician through the confirmation and repair sequence for the code. It is drawn from Detroit Power Service Literature and republished by TruckFaultCodes.com (2017).
With the ignition off, the technician disconnects the sensor and the 120-pin MCM connector, measures resistance across the sensor pins, and repairs either a pin-to-pin short or a short to ground in the harness running to pins 86 and 88 of the MCM.
Detroit compressor inlet sensor document details
| Brand | Detroit |
| Model coverage | DD Series (EPA 2007-Current) |
| System / Group | Diagnostic Trouble Codes (DTCs) |
| Fault code | SPN 1172 FMI 4 |
| Source | Detroit Power Service Literature |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Ignition and sensor disconnection
- 120-pin MCM connector disconnection
- Resistance measurement across sensor pins
- Short-circuit and short-to-ground repair
Applicable truck models
This fault code troubleshooting procedure applies to Detroit DD Series engines built to EPA 2007 and later emissions standards, covering all model years within the DD Series DTC set. Use it alongside a diesel diagnostic tool such as DiagnosticLink or ServiceLink to read live data and confirm the code before any parts are replaced. For engine coverage and official service resources, visit the Detroit Diesel official website.
Who needs this Detroit compressor inlet sensor manual
Fleet technicians, mobile diesel mechanics and workshop owners rely on this reference before opening the SPN 1172 FMI 4 code with a scan tool. Following the documented sequence avoids replacing good parts and clarifies whether the concern lies in wiring, a sensor, or a mechanical component.
The full SPN 1172 FMI 4 PDF is available in the DiagTechPro manuals library; a free account is required to download.
Related manuals library
