Diagnostic Overview
Cummins fault code 2961 is commonly tied to EGR valve or EGR flow performance. The ECM may detect that the EGR system is not responding correctly, which can affect emissions, turbo response, combustion temperature, and soot output. Causes include carbon buildup, sticking EGR valve, restricted EGR cooler, faulty EGR pressure sensor, plugged sensor tubes, or wiring problems. The first checks should include EGR actuator movement, pressure sensor data, cooler restriction, and related boost or exhaust leaks.