S40 Audio System Failure

I had a similar radio silence problem in my S40. Does it affect all audio sources - radio, USB audio, auxiliary input? A completely dead sound system points to a few common culprits. First, check the fuses related to the audio system. The fuse box location can be found in your car's manual. Second, inspect the wiring connections to the head unit. Sometimes a loose connector can cut off all power.

Yes, it affects all audio sources. Where exactly is the head unit located in the S40? And if the wiring is fine, what would be the next thing to check?

The head unit is integrated into the center console. If the wiring seems secure and the fuses are intact, the problem could be deeper within the head unit itself or the amplifier, if your car has one. To properly diagnose this you’d need specialized tools. I recommend a workshop.

I took it to a local workshop and they confirmed the bass speaker was indeed defective. The repair cost was 280€.