Lexus RX 2004-09 :: Error 4 On CD Player

I am able to reproduce an error on my 2005's audio system. What "Error 4" means? I have to actually turn off the car to reset the CD player.

Here's how I reproduce it:

Background:It's a non-ML system

6-CD changer, cassette, AM/FM

I have six CD's loaded into the system

Steps:When listening to FM radio, push the CD button

Press the "Disk" up-arrow button rapidly (it is the radio station preset #4 button) to change disks. I usually cycle through five or six rapid disk changes, normally going from Disk 1 to Disk 6, in a fast manner.

Sure enough, after the fourth or fifth (maybe sixth) button press, "Error 4" flashes on the display. At this point, I can't do anything with the CD player. I can, however, switch to radio and listen as usual.

To reset the error message and to begin using the CD player again, I have to turn off the ignition. Turning off just the audio system doesn't reset the error.