Pinpoint Test 5: Loud Popping Sound When Cycling The Ignition

PINPOINT TEST 5: LOUD POPPING SOUND WHEN CYCLING THE IGNITION

Normal Operation

Voltage is sent through the start input circuit (GY/V) to the audio control module (ACM) with the key in START. Upon receiving this signal, the ACM mutes all speaker outputs to eliminate the possibility of voltage spikes producing a popping noise through the speakers.If equipped with a subwoofer, the ACM disables the subwoofer while the key is in START by keeping the enable signal below 0.4 volt on circuit (V/R). If there is a short to voltage on circuit (V/R), distortion is heard in the subwoofer whenever the ACM is powered up, and that should be the primary concern addressed. If the subwoofer has distorted sound, see Pinpoint Test 4: The Subwoofer Is Inoperative/Does Not Operate Correctly.

Possible Causes
- Fuse
- Wiring, terminals or connectors
- Subwoofer (if equipped)
- ACM

Diagnostic Procedure

CAUTION:Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.