Circuit/System Description
WARNING: This page is about a different car, the 2008 Suzuki XL7. However, it is still accessible from the selected car via links, so may be relevant.
The Passkey III+ theft deterrent module (TDM) monitors the 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 low speed GMLAN serial data message is greater than 9 volts, then DTC B1424 00 sets.