CMP Actuator System Performance Diagnostics
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2005 Isuzu Ascender, 2005 GMC Envoy XUV, 2005 GMC Envoy XL, 2005 GMC Envoy, and 2005 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The PCM monitors the performance of the CMP Actuator system by monitoring the actual and desired positions of a cam phaser. If the difference between the actual and desired position is more than a calibrated angle for more than a calibrated amount of time, a DTC will set.