P0342, P0347, P0367, P0392
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 CMP sensor signal voltage is always low and the ECM detects no pulses from the CMP sensor for greater than 4 seconds, or cumulative of 50 seconds.