I have not worked on this model as of yet, but I've been reading some other posts on this problem, you have 2 control boards, other members have found one of the control boards had burnt spots on them, and another found the connector pins in them have been coming out on the control board itself.
So I'd check both your control boards first and check the connectors to the control boards.
I finally broke down and called a certified Frigidaire service man. ( $150.00 Plus for first 15 minutes and $80 hr there after ) He spoke with the factory tech and after conducting some tests they decided the problem was in a plug on the bottom of the washer drum. After the service man left I ran a continuity test on the plug and found it to be good. Then I ran a continuity test from the main circuit board on the back of the machine to this plug and found one of the wires was open. I went back to the plug and pulled on the open wire. It was broken about 6" from the plug under a very tight tie wrap. I spliced a piece of wire across the break. The machine is now working properly.