I had an F7 error code flash up on the front panel of my LG electric range intermittently during the pre-heat cycle that was increasing in frequency.
When it happened, the only solution was to shut everything down and restart the pre-heat cycle. Even having done so, sometimes it worked and sometimes it didn't. I tried pulling the plug for half and hour or so to attempt to reset the range electronics...no impact to the issue.
After doing some research online across various LG-specific websites and Reddits, I came to the conclusion that there were a number of common part failures that contributed to that same F7 issue that many LG owners were experiencing.
I ordered three parts:
1) Thermistor (part# EBG61305805)
2) Thermostat (part# 6930W1A003X)
3) PWB Sub-Assembly Board (part# 6871W1N012B)
Installation/replacement time was 15 minutes...could not have been easier. Most of the time spent was removing the back panel. With the back panel off, everything needing replacement was visible and easily accessible.
Installing the listed parts fixed my F7 error code issue.
This was a VERY easy job that saved me hundreds of dollars over the cost of calling an appliance repairman and about $1000 over the cost of replacing the range with another similar LG range.