From my memory (not necessarily a good one) I think that's F3E1 - exhaust thermistor shorted or open. If it is F1E3 that is wrong control board which seems much less likely. I may be totally wrong - all codes tend to blend together after a while. SO you should go to tech sheet first.

The tech sheet on that machine is under console. It'll have the correct code list in it, if it contradicts me trust it. You'd use a putty knife or paint scraper and slide under the front corners of the console to compress those clips and release front edge, but 1st you'll need to pull a few 1/4" screws out of back edge where plastic meets metal panel to fully free it. There are live wires inside so take care and unplug it before you stick any part of you or a tool in there.

The exhaust thermistor is a white diamond shaped sensor about 2"x1" located behind the duct where the filter lives, you can see it looking in from the right side. That lower panel easily comes off with similar clips as the top console, just slide the tool in from edges until you locate them. You push them downward from the front with the tool.

The thermistor is part # WP8577274. If bad the machine control cannot see exhaust temps and will run and probably heat for a few before it realizes it's not seeing heat in exhaust.