65 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.
Find a Cummins code by searching below, or browse the table. Codes on file by system:
| Code | System | Symptom | Full fix |
|---|---|---|---|
| 1117 (SPN 627 FMI 2) | — | Engine won't start; Sudden power loss while driving; Scanner drops connection. | View fix |
| 122 (SPN 102 FMI 3) | — | Significant power derate; Black smoke; Engine may feel "choked" or "lazy." | View fix |
| 131 (SPN 91 FMI 3) | — | Engine stuck at idle; No throttle response; Red Stop Lamp may be active. | View fix |
| 135 (SPN 100 FMI 3) | — | Oil pressure gauge pinned at max; Warning light active; No engine protection for oil pressure. | View fix |
| 145 (SPN 110 FMI 3) | — | Engine fan runs 100%; Gauge pinned at zero/cold; Engine over-fuels on hot start (black smoke). | View fix |
| 151 (SPN 110 FMI 0) | — | Progressive engine derate; Shutdown protection active; Fan at 100%. | View fix |
| 153 (SPN 105 FMI 3) | — | High idle; Excessive black smoke; Cooling fan locked on 100%. | View fix |
| 1896 (SPN 2791 FMI 13) | — | Power loss (derate); Black smoke; Rough idle; Increased soot load in DPF. | View fix |
| 2962 | Emissions | High Exhaust Temp / Derate | View fix |
| 3226-4 | Emissions | Active Regen Inhibited | View fix |
| 3382 (FMI 2) | Lubrication | Derate / Shutdown | View fix |
| 5177 | Turbo | Severe Derate / VGT Frozen | View fix |
| 559 (SPN 157 FMI 18) | — | Engine bogs under load; Hard starting; Misfire; Sudden shutdown. | View fix |
| Cummins 111 (629-12) | Control | No Start / No Comm. | View fix |
| Cummins 112/113/114 (635) | Turbo | Turbo Lag / Low Boost. | View fix |
| Cummins 115 (190-2) | Timing | Crank, No Start. | View fix |
| Cummins 116 (156-3) | Fuel System | Limp Mode / Low Rail Pressure. | View fix |
| Cummins 117 (SPN 156 FMI 4) | — | Engine stalling; Hard start; Severe power derate; Possible white smoke. | View fix |
| Cummins 118 (SPN 157 FMI 3) | — | Loud engine knock; Severe power loss (Limp Mode); Check Engine Light. | View fix |
| Cummins 119 (SPN 135 FMI 4) | — | Low oil pressure alarm; 0 PSI on gauge; Engine may shutdown automatically. | View fix |
| Cummins 144 (SPN 110 FMI 4) | — | Fan stays on 100%; Gauge pinned to Hot; Hard starting in cold weather; Engine derate. | View fix |
| Cummins 221 | Air Intake | Engine Derate / Active CEL | View fix |
| Cummins 3382 (SPN:100 / FMI:2) | Lubrication | Engine Derate / Warning Light | View fix |
| Cummins 351 (3597-12) | Power | Engine Stumbles / Dies. | View 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 |
| FC 1922 | — | Filter light flashes. If ignored, engine will severely derate and eventually "Lock Out." | View fix |
| FC 234 | — | Engine speed has exceeded the safety threshold. Possible fuel system fault. | View fix |
| FC 441 | — | ECM may lose communication; engine stumbles or display flickers. | View fix |
| P000F | Fuel System | Sudden Engine Shutdown | View fix |
| P00AF | Turbo | Severe Derate | View fix |
| P0251 | Fuel System | Engine Cuts Out under Load / Misfire | View fix |
| P0252 | Fuel System | Engine Surges under Load / Cuts Out | View fix |
| SPN 100 FMI 1 | Lubrication | Engine Shutdown | View fix |
| SPN 100 FMI 2 | Lubrication | Stop Engine Light | View fix |
| SPN 103 FMI 2 | — | Turbo "whining"; Erratic boost; Low power; Whistling sound under load. | View fix |
| SPN 105 FMI 3 | — | High idle; Excessive black smoke; Fan stays on 100% of the time. | View fix |
| SPN 110 FMI 0 | — | Engine fan at 100% duty cycle; Significant power loss (Derate); High temp alarm; Potential engine shutdown. | View fix |
| SPN 111 FMI 1 | Cooling | Engine Shutdown | View fix |
| SPN 132 FMI 2 | Air Intake | Black Smoke / Engine Sags | View fix |
| SPN 157 FMI 1 | — | Hard starting; Engine stalling under load; Misfiring; Severe power loss. | View fix |
| SPN 157 FMI 18 | Emissions | Derate (5 mph / 8 kph). The truck is restricted to "crawl" speed. | View fix |
| SPN 190 FMI 0 | — | High-pitched engine whine; Sudden surge in RPM; Possible "Runaway" if oil-fed; Check Engine Light. | View fix |
| SPN 3031 (FMI 2) | Exhaust (SCR) | Inducement / 5-MPH Derate. | View fix |
| SPN 3216 FMI 20 | Aftertreatment | Aftertreatment Derate | View fix |
| SPN 3216 FMI 20 | — | DEF usage is high or low; Frequent parked regens; "Derate" timer may start; Check engine light. | View fix |
| SPN 3216 FMI 3 | Emissions | SCR Engine Derate / MIL On | View fix |
| SPN 3242 FMI 15 | Emissions / DPF | Regen Aborted / High EGT Warning | View fix |
| SPN 3251 FMI 0 | Aftertreatment | High DPF Differential Pressure | View fix |
| SPN 3251 FMI 00 | Emissions / Exhaust | High Soot Level / Forced Regen Locked | View fix |
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