2009 GMC Yukon Owner's Manual - Page 161

When the System Does Not Seem to Work Properly If the URPA system will not activate due to a temporary condition, the message PARK ASSIST OFF will be displayed on the DIC and a red light will be shown on the rear URPA display when the shift lever is moved into R (Reverse). This occurs under the following conditions: Side Blind Zone Alert (SBZA) The vehicle may have a Side Blind Zone Alert (SBZA) system. Read this entire section before using the system. The SBZA system operates on a radio frequency subject to Federal Communications Commission (FCC) Rules and with Industry Canada. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: 1. This device may not cause harmful interference. 2. This device must accept any interference received, including interference that may cause undesired operation. This device complies with RSS-310 of Industry Canada. Operation is subject to the following two conditions: 1. This device may not cause harmful interference. 2. This device must accept any interference received, including interference that may cause undesired operation. Frequency of operation: 24.05GHz - 24.25GHz Field Strength: Not greater than 2.5V/m peak (0.25V/m average) at a distance of 3m. • The driver disables the system. • The ultrasonic sensors are not clean. Keep the vehicle's rear bumper free of mud, dirt, snow, ice and slush. For cleaning instructions, see Washing Your Vehicle on page 5-110. • A trailer was attached to the vehicle, or a bicycle or an object was hanging out of the liftgate during the last drive cycle, the red light may illuminate in the rear display. Once the attached object is removed, URPA will return to normal operation. A tow bar is attached to the vehicle. The vehicle's bumper is damaged. Take the vehicle to your dealer/retailer to repair the system. such as vibrations from a jackhammer or the compression of air brakes on a very large truck. If the system is still disabled, after driving forward at least 15 mph (25 km/h), take the vehicle to your dealer/retailer. • • • Other conditions may affect system performance, 2-55