Audio Unit Self-Diagnosis Function (Base System): Notes

Turn ignition switch to ACC position.
Turn the audio system off.
While pressing the "RPT-SCAN" button, turn the volume control dial clockwise or counterclockwise 30 clicks or more. When the self-diagnosis mode is started, a short beep will be heard.

Fig 1: Turning Volume Control
Courtesy of NISSAN MOTOR CO., U.S.A.
When the self-diagnosis mode is started, all of the display segments will be illuminated.

Fig 2: Screen Display
Courtesy of NISSAN MOTOR CO., U.S.A.