Frigidaire FWS648 electric stove error code

My Frigidaire electric stove model FWS648W-1 is displaying error codes

007 and 009. Does someone here know what the codes mean? I can use the elements on the stove top, but the oven is non-operational. Sometime, the error code would clear, and I could hear the relay click and feel the oven elements warm up, but they will immediately shut down, and the error code would comme back. Sometime the code is 007, but now, code 009 is displayed on a permanent basis. Thanks