Security Indicator Operation
WARNING: This page is about a different car, the 2008 Pontiac G5 and 2008 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The theft deterrent module (TDM) can command the body control module (BCM) to illuminate the security indicator only when the ignition key is in the ON position. If the engine control module (ECM) loses communication with the TDM, the BCM will also detect the loss of communication and will illuminate the security indicator. The security indicator can indicate both malfunctions, indicator ON steady and tamper, indicator flashing. A flashing indicator indicates unauthorized operation.