Conditions for Setting the DTC
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.
C027D 64
The parking brake control module has detected wheel speed on the rear wheels with the parking brake applied.
C028D 00
The parking brake control module has an internal counter which keeps track of dynamic applies. When the counter reaches the threshold value this DTC will set.