I researched your question regarding error code FSE1. I could not find a response regarding a self cleaning oven. If you will provide the model number on the below listed website under "cooking" you may get a detailed response.
It seems that a general "fix" for error codes is to got to your electrical panel and shut off the breaker controlling your device for 1 minute. This resets the device and will reset the error code. (May not fix your issue but will reset code.)
Your manual should have a list of error codes to help you resolve this issue. If you have misplaced the manual, you can also download one for your device from Whirlpool's website as well.
If all else fails here are the U.S. and Canadian telephone numbers under "Contact us". I do not know if this is a pay line or Whirlpool will answer your questions and attempt to resolve at no cost.