Okay so I just had the car hooked up with an am and a subwoofer a few weeks back. Until recently, everything worked ok. The Kenwood CD player is working fine, the amp is working fine, and the subwoofer is working fine. When I put it in radio tuner or CD mode, there is bass coming from the subwoofer, but there is no audio coming from the front or rear speakers. There is a very faint audio heard in the rear when playing the CD songs though, but barely enough to hear. I checked the rear of the CD player and all the wires seemed fine. The RCA cables to the amp and sub are working properly as well. The CD player shows no error and displays normal tracks being played with the exception of audio from the speakers.

Anything else I can check?

Not sure if any of these will solve the problem but check:

Make sure the wire harness is grounded. I used to attach the radio ground to the corresponding ground in the car harness, but lately I have put a ring terminal on the radio ground and bolt it to the metal framework in the center console area.

Check the fuse on the back of the radio. Doubtful that this is the issue, because nothing would work on the radio.

Double-check your speaker wiring from radio to harness.

The problem is fixed...for now. I took it back to the audio place where I got the alarm and wiring installed. He told me that the deck shuts off audio and goes into "protection mode" when there is a loose ground wire. Apparently the wires on my ghetto fabricated speakers (seen in my build thread) were touching the chassis everytime I hit a bump causing it to ground and so the sound turns off. The shop install had nothing to do with it and one of their dudes even fixed and crimped the terminals on securely for free!