Help needed: Subwoofer settings cause crackle

[Dylan2996]

Hi guys, so i've had this pioneer unit in my SUV for a while now (years).

The other day it started producing a crackling noise in all the speakers (doors, dash, sub). When i go into the settings and turn off the subwoofer the problem goes away and everything sounds perfect. 

I disconnected the audio cables from the unit itself and it still makes the noise. I've also tested the amp/sub separately and it works fine. Problem appears to be with the unit itself and only when the subwoofer settings is switched to ON.

Any ideas or suggestions? Thank you in advance!

Equipment: Pioneer AVH-270BT

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