Conditions for Setting the DTC
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The ECM detects that the state of the high side driver and the state of the CMP solenoid control circuit does not match. The ECM will detect an open, high resistance, short to ground, or a short to voltage on the CMP solenoid control circuit, or an open on the low reference circuit, if the condition is present for more than 6 seconds.