The message F1 indicates a failure of the control to sense the water level and replacing the central control is a possibility but there are some things you can check first.
Besides the control the other two things that might cause this problem is the clear plastic pressure hose that runs from the control to the air dome on the side of the tube. The air dome might also be the cause of the F1 message.
Always unplug or de-energize electrical equipment before removing covers or attempting service. Be careful and wear appropriate hand protection when working around sharp metal parts
. I am including an illustrated set of teardown instructions for you (see images below).
If the pressure hose is kinked, blocked or has a small pin hole/leak then that can be the cause of the F1 error. Checking the pressure hose is something you can do if you're comfortable with a little do-it-yourself.
The image below contains the instructions for accessing the control and the pressure hose. Remember to unplug the washer first. Access the hose and with the tub empty remove the hose and blow through it towards the tub. If should blow fairly easily but if you can't blow through it then you'll have to run the hose and check for kinks that might be blocking the air.
If the hose is clear then most likely the control will have to be replaced but after blowing through the hose hook it back up and try the washer and see if the F1 problem repeats.
If the hose is blocked then that would be the cause of the F1 message. The hose with a kink can be fixed. The hose with a pin hole can be replaced but if the hose is not the problem then the air dome on the side of the tub can be blocked and if it can't be cleared then it may be necessary to replace the outer tub to fix this problem.
But first check the hose and see if things improve. If not then submit another question with any additional details for further assistance checking the air dome.
I have included a link that you may use for parts purchases; please click the following
Sears Parts Direct
If you require further assistance please resubmit your question with details of the checks you have made. If you do not feel comfortable attempting to repair the washer yourself, service can be set at the following link:
Sears Home Services