GMC Sierra Owners Manual
Ultrasonic Parking Assist
If available, Ultrasonic Rear Parking Assist (URPA) system uses sensors on the rear bumper to assist with parking and avoiding objects while in R (Reverse). It operates at speeds less than 8 km/h (5 mph).
URPA uses audible beeps to provide distance and system information.
Keep the sensors on the vehicle's rear bumper clean to ensure proper operation.
See Ultrasonic Parking Assist on page 9‑66 for more information.