P2088 and P2090
WARNING: This page is about a different car, the 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects a short to ground in the CMP actuator solenoid circuits when the solenoid is commanded OFF. The condition exists for greater than 1 seconds or a cumulative of 5 seconds.