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Parts for Whirlpool GBD277PDB5 Wall Oven - AppliancePartsPros.com

See the attachment for the tech sheet.

The tech sheet gives the error codes.

Try unplugging the unit for a few minutes to see if the error will reset/clear.

If not then perhaps try the following especially if it also gives a E1, E5 or E6.
Connector Cleaning / Checking
Unplug the unit
Open it up
Remove the ribbon cable from the keypad to the control board at the control board.
Clean the edge connector. Use electronics contact cleaner or isopropyl alcohol.
If it is the type where there is not a connector just the insulation is removed, it can be cleaned with a pencil eraser. Do not use an ink eraser as it is too abrasive.
Check the tracks in the ribbon cable for hairline cracks. A magnifying glass helps here.
Would not hurt to clean the connector on the board. Use electronics contact cleaner or isopropyl alcohol and a tooth brush. Be gentle and do not reconnect till all the solvent evaporates.
Reconnect everything and give it a try.

If the above does nothing then I would replace the keypad first.
Note: There is not a good way to check it as they do not publish the keypad outputs.