Conditions for Setting the DTC
WARNING: This page is about a different car, the 2018 Chevrolet Suburban 3500 HD. However, it is still accessible from the selected car via links, so may be relevant.
P2718, P2727, P281B
Control - Terminal 13, 14 @ X175 = Open - For greater than 1 s
P2720, P2729, P281D
Control - Terminal 13, 14, 1 @ X175 = Short to Ground - For greater than 1 s
P2721, P2730, P281E
Control - Terminal 13, 14, 1 @ X175 = Short to Voltage - For greater than 1 s