My Kenmore range model C970-628091 keeps beeping and flashing an F1 or F3 error code when I try to bake at 400 degrees and whenever I try to use timer for baking. When I press cancel the beeping and error codes cancel out but they come right back on soon after I try to preheat the oven again or try to continue baking. Can any one tell me what the error codes mean or provide a solution to this problem?