Overspeed Warning (Export)
WARNING: This page is about a different car, the 2004 Pontiac Sunfire and 2004 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The radio activates the overspeed warning as requested by the body control module (BCM). The BCM sends a class 2 message to the radio indicating the chime frequency of a medium rate and a continuous duration. The overspeed warning sounds when the BCM senses that the vehicle speed is above 120 km/h via a class 2 message from the powertrain control module (PCM). The overspeed warning turns off when the BCM senses that the vehicle speed is below 110 km/h.