2001 Pontiac Montana Owner's Manual - Page 231

When shifting into REVERSE (R) and an object is detected, one of the following will occur: If the rear parking assist system is not functioning properly, the display will flash red, indicating that there is a problem, unless the disable switch is on. The light will also 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. 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. It will also flash red if your vehicle is moving in REVERSE (R) at a speed greater than 3 mph (5 km/h). 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. 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. A chime will sound the first time an object is detected, if the object is between 20 inches (0.5 m) and 5 feet (1.5 m) away. Rear parking assist can detect objects 3 inches (7.6 cm) and wider, and at least 10 inches (2.5 cm) tall, but cannot detect objects that are above liftgate level. In order for the rear sensors to recognize an object, it must be within operating range. 2-119