11 Cummins diagnostic codes on file — with the full diagnosis, repair steps, and field insights open to read free, no signup required.
Disclaimer: General reference information for trained, qualified technicians only. Codes and procedures vary by model, serial number and software version. Always follow the manufacturer's service manual and your site's safety procedures. Use at your own risk. Not affiliated with or endorsed by any manufacturer.
| Code | System | Symptom | Full fix |
|---|---|---|---|
| Cummins 3712 (SPN:5246 / FMI:0) | Aftertreatment | Final Derate / 5 MPH Limit. | View fix |
| Cummins 6254 (SPN:6254 / FMI:9) | Aftertreatment | Limp Mode / Engine Derate. | View fix |
| SPN 157 FMI 18 | Emissions | Derate (5 mph / 8 kph). The truck is restricted to "crawl" speed. | View fix |
| SPN 3216 FMI 20 | Aftertreatment | Aftertreatment Derate | View fix |
| SPN 3216 FMI 3 | Emissions | SCR Engine Derate / MIL On | View fix |
| SPN 3251 FMI 0 | Aftertreatment | High DPF Differential Pressure | View fix |
| SPN 3719 FMI 15 | Aftertreatment | Regen Required Soon | View fix |
| SPN 4334 FMI 16 | Aftertreatment | DEF Pressure High / Derate. | View fix |
| SPN 5246 FMI 0 | Exhaust | 5-MPH Derate Active. | View fix |
| SPN 5246 FMI 15 | Aftertreatment | Derate (Speed limited to 5 mph) | View fix |
| SPN: 3582 FMI: 2 | Aftertreatment | SCR System Fault / Derate. | View fix |
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