Test D: Loud Popping Sound When Cycling The Ignition Switch - Except Navigation

PINPOINT TEST D: LOUD POPPING SOUND WHEN CYCLING THE IGNITION SWITCH - EXCEPT NAVIGATION

D1:

D2-D4:

D4 Continued:

Normal Operation
When the key is placed in START, voltage is sent to the audio unit through circuit 1000 (RD/BK). When the audio unit receives this signal, it mutes the subwoofer amplifier through circuit 173 (DG/VT). This prevents a voltage surge in the speaker circuits, which could result in a popping noise. After the key is removed from START, the audio unit directs audio signals to the speakers through separate positive and negative circuits.

Possible Causes
- Fuse
- Circuit 173 (DG/VT) open or short to ground
- Circuit 1000 (RD/BK) open
- Circuit 1522 (DG) open
- Subwoofer amplifier
- Audio unit