Diesel · Reference Tool

Cummins ISX Fault Code Lookup

0+ real Cummins ISX and ISX15 (CM570 / CM870 / CM2250 / CM2350) fault codes. Search by fault number, SPN, or symptom. See likely causes and the first three diagnostic checks a dealer tech would run.

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Full ISX diagnostic course with wiring, aftertreatment, and case studies — included with Pro.

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Case-study diagnostic worksheet (PDF)

Print one per case study. Intake · fault table · DVOM tests · circuit sketch · root-cause & sign-off.

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Diagnose it right the first time

Fault codes are only step one. The full Cummins ISX Diagnostics & Fault Code Mastery course walks you through wiring diagrams, SPN/FMI logic, DPF regen strategy, DEF/SCR troubleshooting, and real case studies from the shop floor.

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