If I understand what you're saying correctly, just hitting the stereo button by itself wouldn't cause the amp to shut down, unless the volume was very high and caused an amp overload situation OR unless the input signal from TV was too high.
I don't have any experience personally with this error - never encountered an amp shutdown in any of the 3 Elite receivers I've owned. But others here have seen it, some have reported it after a power surge. Some have had to send it in for service menu reset or repair. But I think some have tried a "soft" reset to clear the error & gotten it to work again.
Please read this post from CHP_VR in its entirety in this thread & see if this describes your situation and if you want to proceed before calling Pioneer:http://www.avsforum.com/avs-vb/showt...3#post16754063
From the post, you can try the following soft reset first & see if that clears the error and allows the amp to come up again.
"you can "release" the error by pressing the "down arrow" and the "zone 2 on/off" for 2 seconds"
Before attempting this reset, I'd also recommend -
1. Disconnecting the power cord & just let receiver set for 15-20 minutes
2. Make sure ALL speaker wiring is intact, that there are NO bare wires touching the chassis or hanging out over the receiver's speaker jacks. Even the slightest short could result in amp shutdown.
If this reset doesn't work, then the post describes how to go into the service menu. Going into the service menu is not for beginners since it controls all the receiver's functionality - it's what the repair guys do in the service centers. If you decide to try it, use caution & it's at your risk. Some here have done it with success; there are links to their results.
Hopefully, some of the ones who worked thru this error can give you additional help.