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Parts for Frigidaire PLEB30S8ACA Wall Oven - AppliancePartsPros.com

[COLOR="Blue"]Was thinking the probes were ohming 0.[/COLOR]
May be just semantics but I looked up the F3 code and it says an "open sensor".
This would be infinite ohms not zero ohms.

[COLOR="Blue"]What do I do now?[/COLOR]
If the probe plugs into a harness and then that harness goes to the control board check that the harness pins are clean and properly crimped. You could check the sensor resistance at the control board. Use the meter in both polarities as electronics on the board may effect the reading.

The next check is a bit tricky. You have to get to the solder side of the control board. Looks like it un-clips from the plastic case and then has to be gently bent back. The bare wires at one end of the board are hard wired so that is the hinge side.
Now check the solder connections at the sensor plug for clod solder etc. Cold solder joints often have pin holes and/or are a duller silver color.
Gently wiggle the sensor plug while watching the solder side to see if the pins move in the solder.
Check that the circuit trails going to the plug do not have cracks.
A magnifying glas is useful when checking pins etc.

If all OK you probably need a new control board/timer.
Unfortunately it does not look like the control board is available but I would call them just to be sure.

there are companies out there that will fix obsolete boards just Google "appliance timer repair".
Yours may be a problem as if I understand your post correctly, the fault is intermittent so it may be hard for them to troubleshoot the problem.