Park Aid
With RPA and if equipped with FPA, when the vehicle is traveling at less than 8 km/h, sensors on the bumpers can detect objects up to 2.5 m (8 ft) behind the vehicle and 1.2 m (4 ft) in front of the vehicle, within a zone 25 cm (10 in) above the ground and below the bumper level. These detection distances may be shorter during warmer or wetter weather. Blocked sensors will not detect objects and may also cause false detections. Keep the sensors clean of dirt, mud, snow, ice, and slush; and clean the sensors after washing in freezing temperatures.

The instrument cluster may display Park Assist distance bars, which show the distance to an object and the location of the object detected by the Park Assist system. As the object gets closer, more bars light up and the bars change color from yellow to amber to red.
When an object is first detected behind the vehicle, one audible beep will sound from the rear or both sides, and the Alert Seat will pulse two times. When the object is very close (<0.6 m (2 ft) behind the vehicle or <0.3 m (1 ft) in front of the vehicle), five beeps will sound from the front or rear, depending on the object location, or from both sides, and the Alert Seat will pulse five times. The FPA warning tones are higher than the RPA warning tones.
Test yourself
A quick GMC Terrain quiz: every answer comes with an explanation and a link to the manual page.