Actions Taken When the DTC Sets
WARNING: This page is about a different car, the 2019 Buick Cascada, 2018 Buick Cascada, and 2017 Buick Cascada. However, it is still accessible from the selected car via links, so may be relevant.
DTCs listed in the DTC Descriptor Category = Type C DTC
The control module K20 uses the gear selector lever position sent by the control module K71 over serial data to determine park/neutral for engine starting.