Test I: Loud Popping Sound When Cycling The Ignition
PINPOINT TEST I: LOUD POPPING SOUND WHEN CYCLING THE IGNITIONI1:
I1-I4:
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 speaker pops during engine cranking.
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.
For the THX(R) audio system, the audio unit disables the THX(R) amplifier while the key is in START by keeping the enable signal below 0.4 volts.
Possible Causes
- Fuse
- Circuit CBP28 (GY/VT) open
- Subwoofer (Audiophile)
- THX(R) amplifier
- Audio unit