I have a 2001 S2000, Honda stock radio with Lucid

 

Do you have the Lucid plug and play harness that you connect the rear speakers to? I'm talking about the one that allows you to "mute" all the speakers when you push the mute button. This harness incorporates some sort of circuit that powers OFF the HU when it mutes but retains the memory circuit so the code is kept. The normal mute function simply disconnects the door speakers (on an otherwise stock HU). It may be this harness has gotten old and the power shut off circuit is now not working right.
Since the accessory socket share one of the HU fuses, it also shares a common circuit. Maybe with age, that circuit (which includes the Lucid harness) can no longer accommodate the extra draw of your air pump.

 

XVIPER,

Yes, I have the Lucid wiring harness. I will disconnect it and try it in "stock" mode and see if the problem persists.

Thanks for the suggestion,

Keith