Test E: Loud Popping Sound When Cycling The Ignition

PINPOINT TEST E: LOUD POPPING SOUND WHEN CYCLING THE IGNITION

Normal Operation
Voltage is sent through the start input circuit CBP28 (GY/VT) to the audio unit with the key in START. Upon receiving this signal, the audio unit mutes all speaker outputs to eliminate the possibility of voltage spikes producing a popping noise through the speakers.

For the Audiophile audio system, the audio unit disables the subwoofer while the key is in START by keeping the enable signal below 0.4 volts on circuit SME23 (VT/RD). If there is a short to voltage on circuit SME23 (VT/RD), distortion will be heard in the subwoofer whenever the audio unit is powered up, and that should be the primary concern addressed. If the subwoofer has distorted sound, GO to Pinpoint Test D. Test D: The Subwoofer Is Inoperative/Does Not Operate Correctly - Audiophile

This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Subwoofer (Audiophile)
- Audio unit

E1-E2: