I had that happen to me on my Integra. I had to reset it and run aud. I had it running in 2.1 for stereo use only. But hooked up my blu-ray player and the sub was not on. It was on PCM only and I could not find a way to get it changed, so I just reset it and works good. Now waiting for the Dayton center to make it 3.1 to play DD, DTS, etc.