Detroit fault code SPN 3057 FMI 2 is the TruckFaultCodes.com diagnostic sheet for the SCR Outlet NOx Sensor – Error 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 | 0.3 MB |
| Format | |
| Language | English |
Document table of contents
- Fault code identification (SPN 3057 / FMI 2)
- Description and enabling conditions
- Related SPN 5357 checks
- Parameter charting and parked regeneration
- NOx conversion efficiency decision
SPN 3057 FMI 2 troubleshooting steps
The sheet monitors SCR Outlet NOx. Enabling conditions are 1000 to 1800 rpm, 35 to 100 percent load, steady cruise. Typical duration is 8 minutes, the dash lamps are MIL, and the engine reaction is none.
With the diesel diagnostic tool connected, the routine first repairs any SPN 5357 FMI 16 or 18 faults. Engine speed, SCR inlet and outlet temperatures, both NOx sensors and NOx conversion efficiency are charted, then a parked regeneration is performed. If NOx conversion efficiency rises above 70 percent during the regeneration the faults are cleared; if it does not, the SCR outlet NOx sensor is replaced using the EPA10 outlet NOx sensor removal procedure in Power Service Literature.
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 3057 FMI 2 manual
Technicians verifying whether an SCR outlet NOx sensor is truly faulty use this sheet to read conversion efficiency during a parked regeneration before replacing the sensor. 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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