115 Caterpillar 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 |
|---|---|---|---|
| SPN 157 FMI 18 | — | Engine Bogging. | View fix |
| SPN 168 FMI 1 | Electrical | Slow Crank / ECM Reset | View fix |
| SPN 168 FMI 2 | — | Lights flickering; Radio resetting; Random "ghost" codes across different systems; Hard starting. | View fix |
| SPN 177 FMI 0 | — | Erratic shifting; Transmission slipping; "Hot oil" smell; Warning light on dash. | View fix |
| SPN 177 FMI 16 | Transmission | Transmission Temperature Alarm / Derate | View fix |
| SPN 190 FMI 0 | Engine | Engine Shuts Down / Red Light | View fix |
| SPN 190 FMI 0 | Engine | Logging / Overspeed | View fix |
| SPN 3251 FMI 0 | Emissions / DPF | Active Derate Warning / DPF Light | View fix |
| SPN 3547 FMI 3 | Aftertreatment | High Idle / MIL On | View fix |
| SPN 4364 FMI 18 | — | Emission Derate. | View fix |
| SPN 520215 FMI 03 | Hydraulics / Blade | Blade Lift Joystick Drift / No Response | View fix |
| SPN 524285 FMI 2 | Transmission | Transmission Slippage / Erratic Shift | View fix |
| SPN 524286 FMI 14 | Transmission | Harsh Reverse Shifts / Trans Warning | View fix |
| SPN 639 FMI 9 | — | Multiple gauges "dropping out"; Engine may stay at idle; Machine won't move; Multiple controllers "Timed Out." | View fix |
| SPN 94 FMI 3 | — | Engine "stumble" under load; Hard starting; Low power. | View fix |
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