Conditions for Setting the DTC

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

The EBCM diagnoses a fault condition in the master cylinder pressure sensor, and sends a serial data message to the trailer brake control module.
The EBCM diagnoses a fault condition in the wheel speed sensors, and sends a serial data message to the trailer brake control module.