Erasing Channels
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
To erase programmed channels, press and hold the two outside buttons until the lights on the GDO transmitter begins to flash. Once the LEDs begin to flash, release both buttons; all learned codes are now erased.
Individual channels cannot be erased, but can be reprogrammed using the procedures above.