Conditions for Setting the DTC
WARNING: This page is about a different car, the 2004 Pontiac Grand Prix. However, it is still accessible from the selected car via links, so may be relevant.
If the BCM senses the security system sensor supply circuit is short to battery positive when the ignition is in the OFF position DTC B2945 will be set as a current DTC. If the DTC is current when the ignition is switched to the ON position the DTC will become a history DTC.