RAM 2500 2021 Owner's Manual page 217

If an obstacle is detected in the left and/or right rear region, the display will show a single arc in the left and/or right rear region and the system will
produce a tone. As the vehicle moves closer to the obstacle, the display will show the single arc moving closer to the vehicle and the tone will change
from a single 1/2 second tone to slow, to fast, to continuous.
The vehicle is close to the obstacle when the display shows one flashing arc and sounds a continuous tone. The following chart shows the warning alert
operation when the system is detecting an obstacle:
Greater than
Rear Distance
79 inches
(inches/cm)
(200 cm)
Audible Alert
None
Chime
Arcs-Left None
Arcs-Center None
Arcs-Right None
Radio Volume
No
Reduced
Front Distance Greater than 47 inches
(inches/cm) (120 cm)
Audible Alert Chime
Arcs-Left
WARNING ALERTS FOR REAR
79-59 inches 59-47 inches
(200-150 cm) (150-120 cm)
Single 1/2
Slow
Second Tone
None None
10th Solid 9th Solid
None None
Yes Yes
WARNING ALERTS FOR FRONT
47-39 inches
(120-100 cm)
None None
None None
47-39 inches 39-25 inches
(120-100 cm) (100-65 cm)
Slow Fast
None None
8th Solid 7th Flashing
None None
Yes Yes
39-25 inches 25-12 inches
(100-65 cm) (65-30 cm)
None Fast
None 3rd Flashing
STARTING AND OPERATING 215
Less than
25-12 inches
12 inches
(65-30 cm)
(30 cm)
Fast Continuous
6th Flashing 5th Flashing
6th Flashing 5th Flashing
6th Flashing 5th Flashing
Yes Yes
Less than 12 inches
(30 cm)
Continuous
4th Flashing
4