GM Service Manual Online
For 1990-2009 cars only

Ultrasonic Rear Parking Assist (URPA) can help a driver determine how close an object is to the rear bumper within a given area.

The rear parking assist display is located inside the vehicle, above the rear window. It has 3 indicators that can be seen through the rearview mirror or by turning around. (The URPA is equipped with an on/off switch located in the overhead console and the URPA system can be disabled from the on/off switch.)

During bulb check, the 3 indicators on the display illuminate for 2 seconds to let you know that the system is working. The URPA activates when the following conditions are present:

    • The shift lever is moved into REVERSE (R).
    • The vehicle speed is less than 5 km/h (3 mph).

The URPA senses how close your vehicle is to an object. The distance is determined by the four ultrasonic sensors located on the rear bumper. When shifting into REVERSE and an object is detected, one of the following will occur:

    • Less than 12 in (0.3 m) -- Amber (Outside), Amber (Middle), and Red (Outside) indicators flash and there is a continuous chime.
    • 12 to 20 in (0.3 to 0.5 m) -- Amber (Outside), Amber (Middle), and Red (Outside) indicators illuminate and there is a continuous chime.
    • 20 to 40 in (0.5 to 1.0 m) -- Amber (Outside), and Amber (Middle) indicators illuminate and the module chimes one time on the first detection of an object in this area.
    • 40 in to 5 ft (1.0 to 1.5 m) -- Amber (Outside) indicator illuminates and the module chimes one time on the first detection of an object in this area.

URPA can detect objects 3 in (7.6 cm) and wider, and at least 10 inches (25.4 cm) tall, but it can not detect objects above the level of the roof. In order for the rear sensors to recognize an object, it must be within operating range.

If the URPA system is not functioning properly, the display flashes the red indicator, indicating that there is a problem and the on-board diagnostics need to be entered. Refer to On-Board Diagnostic Features .