To test for VCT noise:

1. Place the transmission in park or neutral
2. Bring engine oil temperature to 160° F (71° C) or above as indicated by the scan tool "EOT" PID.
3. Allow engine to idle, and determine if noise is noticeable.
4. Set engine speed to over 1200 RPM (if noise is a VCT knock, the noise should disappear).
5. Return engine speed to idle (verify knock returns).

If the noise intensity is more than a lightly audible knock at hot idle under 1200 RPM at engine operating temperature, replace the cam phaser

Hope that helps you figure it out