Turn off the audio unit.

Push and hold the ‘‘No. 1’’ and ‘‘No. 3’’ buttons.While holding the buttons, push the ‘‘VOL push PWR’’ knob to ON.

Release the buttons and the speaker check mode will begin. Low-Frequency hum should sound for one speaker.

Change the test speaker by push the ‘‘SKIP’’ button. If find no sound speaker(s), check the speaker, and harness.

The self-diagnostic function will end when the audio unit is turned off, or the ignition switch is turned off.