Rough Idle — Possible Fault Codes

Found 3 fault codes associated with rough idle. Codes are sorted by severity — check STOP ENGINE codes first.

SPN 1322 FMI 31

Misfire Detected on Cylinder 6

Cummins ISX15 • Component: Cylinder 6 Injector / Valve Train • J1939

🟡 CHECK AT NEXT STOP

MID 128 SID 1 FMI 5

Injector Cylinder 1 Circuit

Cummins ISX15 • Component: Fuel Injector #1 Solenoid Circuit • J1587

🟡 CHECK AT NEXT STOP

MID 128 PSID 90 FMI 4

EGR Differential Pressure Sensor

Volvo D13 • Component: EGR Differential Pressure Sensor / EGR Valve • J1587

🟠 CHECK SOON

⚠️ Diagnostic Note: Symptoms can have multiple root causes. Always verify with a diagnostic scan tool before replacing parts. The fault codes listed above are possible matches for rough idle based on SAE J1939/J1587 fault code definitions and OEM service documentation.