Check The Back Sensor

WARNING: This page is about a different car, the 2011 Subaru Tribeca. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: Before starting inspections, inspect the safety around the rear end of the vehicle.

Turn the ignition switch to ON.
Pull the parking brake and depress the brake, then put the gear in reverse.
Make sure that "On" is lit in the back sensor item. Standard Value: "On" should be lit.
On: Normal

NG: If "On" does not light, check the signal line connection. If there are no problems, the unit could be faulty.