Functional OVERBOOST Monitoring

The 6.7L engine utilizes a closed loop boost pressure controller to maintain desired boost pressure set point under all temperature ranges and engine operating modes. The overboost monitor compares the desired vs. actual measured boost pressure while in a specific range of closed loop boost pressure operation. If the boost pressure governor deviation is greater than the calibrated threshold for 7 seconds, a fault is detected and the P-code is set. The closed loop monitoring window is defined as any inner torque above 50 nm, and any engine speed above 1000 rpm. Torque window and threshold slightly different for dyno cert due to different turbocharger configuration, calibration, and air path response.

This diagnostic will detect a turbo slowly responding or stuck in the primarily closed condition.