CMP Actuator System Performance Diagnostic
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) monitors the performance of the camshaft position (CMP) actuator system by monitoring the calibrated desired position, and the actual position of the camshaft, through the 4X signal of the CMP sensor. If the difference between the actual and desired position is greater than a calibrated angle, for more than a calibrated amount of time, DTC P0011 will set.
For the system descriptions covering the hydraulic/mechanical part of the CMP actuator refer to Camshaft Position (CMP) Actuator and Solenoid Valve Description .