P2089, P2091, P2093, P2095
WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects a short to voltage in the CMP actuator solenoid circuits for greater than 4 seconds or a cumulative of 50 seconds, when the solenoid is commanded ON.