Nigel,
According to the Frigidaire technical documentation, most likely the cause of the problem is a bad Electronic Oven Control (EOC).
Check the wire harness and the P4 connector at the EOC. If the wire harness and the connector are fine, replace the EOC.
- The part number for the EOC is
AP3776965
In order to provide the right part number for the overlay I need the last letter of the model number.
Gene.