Chevrolet Captiva OM C140 Manuals page 278

276 Driving and operating
This system is deactivated when
the vehicle's speed is greater than
approximately 25 km/h (15 mph).
If the alarm sound happens when
shifting the gear to "R" position,
this indicates normal condition.
Warning sound
You can figure out the distance
between your vehicle and
obstacles with the warning sound.