What does PS4 error SU-42118-6 mean?

PS4 system software update error SU-42118-6 is not a software issue. … Till now, you should know the cause of PS4 error SU-42118-6 is the improper assembling of your PS4 hardware. This can also turn off your PS4 randomly. When this issue happens to your PS4, the system will not communicate with the BD-ROM.