Conditions For Setting the DTC: U2006
WARNING: This page is about a different car, the 2002 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
The BCM is the generator of the SPI serial data synchronizing Clock signal. U2006 is set, in the BCM, when the Clock circuit is less than 1.2 v for greater than 5 seconds.