Detroit fault code SPN 3031 FMI 3 is the TruckFaultCodes.com diagnostic sheet for the DEF Tank Temperature Sensor Circuit Failed High condition on Detroit DD-series engines. This 2 pages reference lists the fault identification, monitored conditions where shown, and the step-by-step troubleshooting the technician follows in the shop.
Official document details
| Brand | Detroit |
|---|---|
| Model coverage | Detroit DD Series (EPA 2007-Current) |
| System / Group | DD Series (EPA 2007-Current) / DTCs |
| Publication no. | Not printed; TruckFaultCodes.com reference |
| Year / Revision | 2017 |
| Pages | 2 |
| File size | 0.2 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (SPN 3031 / FMI 3)
- Description and monitored parameters
- Checking for companion codes
- Sensor connector inspection
- Voltage test and circuit repair
SPN 3031 FMI 3 troubleshooting steps
The sheet monitors DEF Tank Temperature Sensor. Typical duration is 2 seconds, the dash lamps are MIL and CEL, and the engine reaction is none.
The two-page routine first checks whether this code is set together with SPN 1761/FMI 3. The DEF tank level and temperature sensor connector is disconnected and inspected for bent, spread or corroded pins, then voltage is measured at the sensor connector. Voltage present indicates a short to power between the sensor and the Aftertreatment Control Module (ACM) 120-pin connector pins 102 or 103, while no voltage indicates an open in the same circuit; each is repaired as directed.
Applicable truck models
This sheet applies to Detroit DD-series diesel engines (the DD13, DD15 and DD16 family) built under the EPA 2007-Current emissions platform, in its EPA10 / GHG14 calibration. Engine and emissions specifications should always be confirmed against the vehicle build; full engine information is published on the Detroit Diesel official site.
Who needs this SPN 3031 FMI 3 manual
Technicians with a DEF tank temperature sensor circuit reading high use this sheet to tell a short to power apart from an open circuit back to the ACM. It is a quick bench reference rather than a full workshop manual, so the named removal steps still route back to Power Service Literature and, where escalation is needed, to the Detroit Customer Support Center.
The full PDF is available in the DiagTechPro manuals library; a free account is required to download it.
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