Circuit/System Description
WARNING: This page is about a different car, the 2013 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The remote control door lock receiver (RCDLR) monitors the key in ignition switch signal circuit as a means of initiating transmitter authentication. When the ignition control knob is pressed, the key in ignition switch (part of the ignition switch assembly) is closed. This grounds the key in ignition switch signal circuit and the RCDLR will being the transmitter authentication process.
If a fault exists on the key in ignition switch signal circuit or within the switch itself, transmitter authentication will not initiate when pressing the ignition control knob. Instead, transmitter authentication will only occur when depressing the brake pedal.