GM Service Manual Online
For 1990-2009 cars only

If your vehicle has the Ultrasonic Rear Parking Assist (URPA) system it is designed to help you park while in Reverse (R). It operates only at speeds less than 5 mph (8 km/h). URPA helps make parking easier and helps you avoid colliding with objects such as parked vehicles. The URPA system detects objects that are close to the rear of the vehicle which are at least 10 inches (25.4 cm) off the ground and below hood or trunk level. The system detects objects up to 8 feet (2.5 m) behind your vehicle. The URPA sensors determine how close these objects are from your bumper within this area.

Caution: The Ultrasonic Rear Park Assist (URPA) system does not replace driver vision. URPA does not:

   • Operate above speeds of 5 mph (8 km/h).
   • Detect objects more than 8 feet (2.5 meters) behind the vehicle. This distance may be less during warmer or humid weather.
   • Detect objects that are below the bumper, underneath the vehicle, or that are very close to the vehicle.
   • Detect children, pedestrians, bicyclists, or pets.
So if you do not use proper care before backing up, you could hit a vehicle, child, pedestrian, bicyclist, or pet, resulting in vehicle damage, injury, or death. Even though the vehicle has the URPA system, always check carefully before backing up by checking behind your vehicle.


Object Number: 1722088  Size: A2

The URPA display is located in the headliner and can be seen by looking over your right shoulder.

The URPA display has three color-coded lights. The lights are used to provide distance and system information, along with beeps that will be heard through the speakers.

If the vehicle has a Driver Information Center (DIC), and PARK ASSIST OFF has been selected, then the vehicle is shifted into REVERSE (R), PARK ASSIST OFF will display on the DIC and one red light in the URPA display will be lit. See DIC Warnings and Messages for more information.

URPA automatically turns back on each time the vehicle is started.

How the System Works

When the shift lever is moved into REVERSE (R), the rear display will briefly come on to let you know the display is operating correctly. URPA comes on automatically when the shift lever is moved into REVERSE (R).

The system does not work at a reverse speed greater than 5 mph (8 km/h). To remind you of this, the red light on the rear display will flash.

To disable URPA, see DIC Operation and Displays for more information.

How the System Works when Backing

If the shift lever is in REVERSE (R), URPA detects objects close to the rear bumper. The first time an object is detected a single beep will sound. If an object is detected at a REVERSE (R) speed between 0 mph (0 km/h) and 5 mph (8 km/h), the following describes what will occur based on your distance to a detected object located behind the vehicle:

    • At distances between 40 inches (1 m) and 8 ft (2.5 m), a single amber light will come on.
    • At distances between 23 inches (0.6 m) and 40 inches (1 m), both amber lights will be on.
    • At distances between 12 inches (0.3 m) and 23 inches (0.6 m), all three lights (amber/amber/red) will be on.
    • At distances less than 12 inches (0.3 m), a beeping sound will repeat for a short time and all three lights (amber/amber/red) will flash.

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 display on the DIC screen and a red light will come on the URPA display when the shift lever is moved into REVERSE (R). This occurs under the following conditions:

    • The parking brake pedal is depressed.
    • A trailer was attached to your vehicle, or a bicycle or an object was hanging out of your trunk during your last drive when you turned off the vehicle. If the attached objects are removed from your vehicle before the start of your next drive, the system will return to normal operation unless an object is detected when the vehicle is shifted into REVERSE (R). If this occurs, URPA assumes the object is still attached, so you will have to wait until the vehicle is driven forward above 15 mph (25 km/h) before URPA will return to normal operation.
    • The ultrasonic sensors need to be kept clean. So, be sure to keep your vehicle's rear bumper free of mud, dirt, snow, ice, and slush. For cleaning instructions, see Washing Your Vehicle . If the DIC still displays the PARK ASSIST OFF message after cleaning the bumper and driving forward at a speed of at least 15 mph (25 km/h), see your dealer/retailer.
    • Other conditions that may affect system performance include vibrations from a jackhammer or the compression of air brakes on a very large truck or other mechanical devices that interfere with URPA performance.

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.

If the vehicle bumper is damaged, the URPA system may not work properly. Take the vehicle to your dealer/retailer to repair the system.