CAN Protection Strategy
WARNING: This page is about a different car, the 2018 Lincoln Navigator. However, it is still accessible from the selected car via links, so may be relevant.
When the perimeter alarm is armed, the BCM monitors the CAN. If a scan tool is connected to the DLC, and an attempt is made to establish a session with the BCM, it activates the perimeter alarm.
Every time the BCM detects an unauthorized access (alarm activates), all BCM programming, PID monitoring and self-test sessions are blocked for 10 minutes. At the end of the 10 minute time period, the traffic horn chirps to indicate the 1 minute of opportunity to communicate with the BCM and program keys if none are available. Refer to: PASSIVE ANTI-THEFT SYSTEM (PATS) .