Prius won’t shift to drive or reverse

A week ago I got the triangle of death. But the vehicle continue to operate. My regular mechanic said it was probably an error two days ago. The vehicle died on the freeway and was towed home. all panel lights come on but many of the screens will not show their information. Prior to this the vehicle had the following conditions. One the air conditioning has not worked since last summer. two there is a rattling sound that comes from under the dashboard when the heat is on and just as I turn the engine on. Rattling seems to occur when heating conditions change. Three a rat is living in Side back seat cushion. Four my mileage is 47 miles per gallon. Five I only have 69,000 miles on the engine. Six the vehicle has not been serviced by a Toyota mechanic and no heating maintenance. Has been performed.