This Detroit coolant outlet circuit reference documents fault code SPN 110/FMI 4 (Engine Coolant Outlet Temperature Circuit Failed Low) for Detroit DD-series engines with the 120-pin MCM harness. 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 coolant outlet circuit troubleshooting overview
This description-style sheet lists the monitored parameter (engine coolant outlet temperature sensor), the always-enabled monitor, the typical two-second duration and the MIL and CEL dash lamps. The corrective action is repairing the short to ground between pin 2 of the coolant-outlet sensor connector and pin 110 of the 120-pin Motor Control Module (MCM) connector. 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 120-pin MCM harness |
| System / group | DTCs — engine coolant outlet temperature sensor circuit |
| Fault code | SPN 110/FMI 4 |
| Source publication | TruckFaultCodes.com (© 2017) |
| Pages | 1 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification — SPN 110/FMI 4
- Monitored parameter and enabling conditions
- Dash lamps (MIL, CEL) and verification at engine idle
- Repair the short to ground: sensor pin 2 to MCM pin 110
Applicable truck models
It applies to Detroit DD-series engines using the 120-pin Motor Control Module (MCM) harness. 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 coolant outlet circuit manual
Technicians who need the exact pin-to-pin repair for a coolant-outlet sensor circuit that has failed low. 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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