Conditions for Setting the DTC
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
B1640 01
A short to voltage is detected on the mirror heating element control circuit while the heated mirrors are inactive.
B1640 02
A short to ground is detected on the mirror heating element control circuit while the heated mirrors are active.