Range keeps giving E0/F3 and E4/F3

My oven starting making a racket when the convection was turned on and I assumed it was a fan. After awhile it quit making the noise but it started giving fault codes [SIZE=3]E0/F3 and E4/F3 and will not stay on. I had a repairman in and replaced the sensors Upper and lower in the oven. No change. I explained that I thought the fan may have quit working, but he felt that it was not the fan. He is saying (after I spent nearly three hundred dollars for parts and labor for sensors) that I need to spend aroung $450.00 for a new control board. [/SIZE]
[SIZE=3]I still think that noisy and now quiet fan may have something to do with this. What do you think?[/SIZE]

[SIZE=3]Thank You,[/SIZE]
[SIZE=3]MaryBethOH[/SIZE]