Great thread. I thought I would post our experience as we have had slightly differing but equally frustrating results with the LC64D62U, LC52D62U, LC42D62U with Crestron. We started with the integrated partner module (Sharp LC-52D64U v1.0)for communication and noticed constant errors being returned from the display. There were a couple of things we noticed. Any polling while the display was off would return:

ERR\x0D

In addition we did have to enable the power on control similar as described above but with some differences. WITH THE DISPLAY ON send the display:

IAVD5 \x0D (3 spaces between the 5 and the \)

and the response was:

OK\x0D

We modified the module to not send any functions or polling to the display while the display was off. This has resolved our error issues almost completely.