Theory Of Operation
WARNING: This page is about a different car, the 2013 Dodge Avenger and 2013 Chrysler 200. However, it is still accessible from the selected car via links, so may be relevant.
For the Variable Camshaft Timing (VCT) to enable, the oil pressure has to be approximately 42 psi. For the VCT to remain enabled the engine oil pressure can not drop below 31 psi.