Diagnostic Aids

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.

DTC C0176 54 does not indicate that a malfunction has occurred. Rather that the PSCM had to limit current to the power steering motor to avoid thermal damage to the power steering system components.
Ensure that no steering components down stream of the power steering gear assembly, universal joints, ball joints or tie rod ends are mechanically binding.