Cummins X15 Fault Codes

🔧 Engine Context: The Cummins ISX15/X15 series is the most common heavy-duty diesel engine in North America, powering Freightliner Cascadia, Kenworth T680, and Peterbilt 579 trucks. Introduced in 2007, the ISX15 has gone through multiple emissions control iterations — from EGR-only to SCR+DEF. Each iteration introduced new fault codes. The most common issues on this series include VGT turbo actuator failures, EGR system problems, and engine protection derate events.