2002 Buick Rendezvous Owner's Manual - Page 219

When the System Does Not Seem to Work Properly The light will flash red when shifting into REVERSE (R) if a trailer was attached to your vehicle, or a bicycle or an object was on the back of, or hanging out of your liftgate during your last drive cycle. The light will continue to flash whenever in REVERSE (R), until your vehicle is driven forward at least 15 mph (25 km/h) without any obstructions behind the vehicle. It may also flash red if the ultrasonic sensors are not kept clean. So be sure to keep your rear bumper free of mud, dirt, snow, ice and slush or the system may not work properly. Other conditions that may affect system performance include things like the vibrations from a jackhammer or the compression of air brakes on a very large truck. If after cleaning the rear bumper and then driving forward at least 15 mph (25 km/h), the display continues to flash red, see your dealer. As always, drivers should use care when backing up a vehicle. Always look behind you, being sure to check for other vehicles, obstructions and blind spots. For cleaning instructions, see "Cleaning Your Vehicle" in the Index. 2-127