I don't have any first hand experience with Electrolux, so I can't tell you much, but here is what the service manual for that range says about that error code:

"F15 Controller self check failed or terminal cutoff open. 1) An F15 error code on the oven controller may indicate the oven controller is not receiving a synchronization signal from the relay board. One easy way to determine this is to power off the unit, power it on and start a Timer for 1 minute before the F15 error code appears. If the timer counts-down normally then the synchronization signal is okay. If the timer stays at 1:00 and does not countdown, then the synchronization signal is missing. If the synchronization signal is missing, check first if the oven relay board is receiving 120VAC correctly (J4 pin 1 and 3). Then check the wiring between connector J2 on the relay board and connector P16 on the oven controller. If AC power and wiring looks good and the problem is still there, replace the relay board. If problem persists, replace the oven controller. 2) The F15 error code may be caused by an oven controller failure. If the synchronization signal has been verified and tested good, replace the oven controller."

I take it you aren't able to even get to the screen where you enter in 1 minute? If that's the case I would be inclined to believe it's the oven controller, but I'd definitely test for the signal before you order anything.

The manual does mention the thermal cutoff switch, but only in relation to the E15 error, not F15. If you're only getting F15 without E15, sounds like one of the 2 boards.

This post was edited by hvtech42 on Tue, May 20, 14 at 22:36

This was the probable cause of my F15 code and it was simple to fix, but it may not help everyone. On pulling out the electrical plug I noticed severe signs of arcing on one of the live input prongs, this would have knocked out half of the input voltage. I filed the prong clean and replaced the receptacle (which turned out to be similarly damaged by arcing). Problem solved for now.