Conditions for Setting the DTC
WARNING: This page is about a different car, the 2016 GMC Acadia, 2016 Chevrolet Traverse, and 2016 Buick Enclave. However, it is still accessible from the selected car via links, so may be relevant.
P258A, P258C
The electronic brake control module detects an open/high resistance on the relay coil control circuit.
P258B
The electronic brake control module detects an excessive difference in vacuum levels between the power brake booster and the manifold absolute pressure (MAP).
P258D
The electronic brake control module detects a short to voltage on the relay control circuit.