iPhone 6 - Audio issues

Hi, I have an iPhone 6 that had contact with water. I used alcohol to clean all connectors and brushed areas that had corrosion and the phone works now. The water seemed to enter from the top, since I found no trace of corrosion near the bottom. Everything functions properly except the speaker. If I raise the volume past the halfway mark it cracks and goes mute. A reboot resolves the issue until I raise it again. Could it be an issue with the dock connector, the speaker itself, or the audio ic U0900?

Thanks.