Model Number: LSG4513BD
Brand: LG
Age: 1-5 years
Oven started to display F9 code intermittently not heating, but some times it reach target temp requested 375p° for example but then it doesn’t stay hot and drops to 150°.
I followed all test procedures and tested oven thermistor and it reads within spec 1090 ohms
Both igniters ( broiler , oven ) tested within spec .
The flow chart in the manual indicates to replace the Relay board
I swapped the relay board with brand new one but the results were inconclusive and about the same plus the new board had not allowed the oven light to function or the chime to work when target temp reached so I ruled it as bad new part out of the box , those functions were restored once I put the original board back on. I
Did try to turn the oven on this morning to and set it to 375° but it displayed F9
So should I order another relay board, main board ? I don’t want to keep throwing parts at it