When the elevator would fail, all of the parameters would go blank in all subsystems. It wouldn't show defaults or 0s the parameters tables are just blank. The weird part about it is the elevator would continue to run and answer hall calls and car calls it just wouldn't open the doors. After a MLR there are no faults displayed and all the parameters will restore to their original values. I thought about going through all the COP connectors but usually when I have a comm error it will show the board Absent on the tool. I've never seen one fail in this manner before. I need to try and get it to fail again while I'm there to plug into each board directly to gather further information. What do you think about changing the CLC software?