Circuit Description
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The four-wheel drive (4WD) low signal circuit is used to notify the transmission control module (TCM) that the vehicle is in 4WD low range.
DTC P2771 is a type B DTC.