When Monitored And Set Condition:
WARNING: This page is about a different car, the 2003 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
When Monitored: When the ignition is on, the ACM monitors the PAB Indicator Driver circuit for voltage from the PAB On-Off Switch indicator circuit.
Set Condition: The code will set if the ACM senses battery voltage on the PAB Indicator Driver circuit.