This light comes on for the reasons below, as well as other related system problems... The electronic brake control module (EBCM) detects a malfunction in the traction control system. The IPC receives class 2 messages from the EBCM requesting illumination of both the service vehicle soon and traction off indicators. The body control module (BCM) detects certain malfunctions in the lighting system. The IPC receives a class 2 message from the BCM requesting illumination. The IPC sends a class 2 message to the BCM indicating that the service vehicle soon indicator is illuminated. The BCM sends a class 2 message to the radio in order to activate an audible warning. The IPC detects a loss of class 2 communications with the BCM. Or any number of exterior light problems, such as daytime running lights (DRL).