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Hello, you have done the most sensible thing, the odds are high that the printed circuit board is bad.
You can try a heat stress test.
Use a hair drier to slowly warm the printed circuit card up to120For a bit warmer, but not over 140F... if there is any change in the error codes or other furnace behavior... the card has a cracked micro circuit that opens and closes as the card expands and contracts... that proves a bad printed circuit card.
No change however does not prove the card is good however... but a change proves the card is definitely bad.
We can go from there.
Let me know how it goes, repeat the test if you need to.