Check Each Vehicle Signal (Display Audio)

Turn the ignition switch to ON, and then while pressing the buttons (a) and (b), press and hold the button (c) for 3 seconds or more.

Fig 1: Screen Display - Buttons
Courtesy of SUBARU OF AMERICA, INC.
The display will switch to the Line Diag screen.

Fig 2: Screen Display - Line Diag Menu
Courtesy of SUBARU OF AMERICA, INC.

CHECK ILLUMINATION
NOTE: Before starting inspections, turn the ignition switch to ON.
1. Turn the lighting switch to level 1.
  Make sure that the bright switch is not turned ON at this time.
2. Make sure that "ON" lights in ILL+ and then the screen becomes dim.
  ON: Normal.
  
  OFF: Abnormal. Check the signal line connector. If there are no problems, the unit could be faulty.
CHECK SPEED SENSOR
NOTE:
- Before starting inspections, check the safety around the vehicle.
- Lift up the vehicle as necessary.
- When the diagnostic trouble code is input in the VDCCM, perform the Clear Memory operation.
1. Move the vehicle 2 to 3 meters (6.6 to 9.8 ft).
2. Check that "ON" is displayed in SPD.
  ON: Normal.
  
  OFF: Abnormal. Check the signal line connection. If there are no problems, the unit could be faulty.
CHECK PARKING BRAKE SIGNAL
1. Pull parking brake lever.
2. Check that "ON" is displayed in PKB.
  ON: Normal.
  
  OFF: Abnormal. Check the signal line connector. If there are no problems, the unit could be faulty.
CHECK BACK SENSOR
NOTE: Before starting inspections, check the safety around the rear end of the vehicle and then turn the ignition switch to ON.
1. Pull the parking brake and depress the brake, then put the gear in reverse.
2. Make sure that "ON" is displayed in REV.
  ON: Normal.
  
  OFF: Abnormal. Check the signal line connection. If there are no problems, the unit could be faulty.