F9 error code on GE Monogram ZDP486NRP6SS

When oven is turned on, error code F9 shows when temp reaches 218. Oven is turned off and back on F9 error shows again after a few degrees hotter.
even when oven placed in clean mode, error shows up. Tried disconnecting/breaker but nothing.
Has anyone experienced this problem and what is solution?

Was this problem ever solved for you? Ours started doing this 3 months ago. So far the latch and the computer board have been replaced but problem has not resolved.