Circuit/System Description
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent module (TDM) monitors the 12V battery positive (B+) voltage available to it. If the voltage at the TDM is between 6-9 volts, and the voltage being reported by a serial data message is greater than 9 volts, then DTC B1424 00 sets.