Check engie light code 51

OK I took it for teat ride again today on the same loop I always go. And the light came on in the same area. And I stopped to see a boat going into the channel and when I started out the light came in within 2 miles of driving. This is after it is warmed up. This sensor has 12 volts going to it to preheat it so I'm thinking it take 10 miles to heat it up and when I turn off the engine and restart it the sensor is heated and can send the code faster? Thanks at this time I'm looking for a different ecu to see if that is the real problem. Even if I get a used one chances are slim I will get one that has the same issue. I may get a new problem but then I know the ecu was the problem all along. Thanks

Well fella's I sold that lebaron yesterday and before I sold it I told the new owner all about the problem and show him all the old parts I exchanged for new parts and he contacted his mechanic and his mechanic told him to get the car if he wanted to because that problem did not affect how it will drive. He gave me what I wanted. And just to show that I did not pawn off a problem he even joined our car club so I will see this car often.

You may consider this closed. And I thanks you for all your help even though we did not find a fix. I still believe it is in the ecu ecm computer whatever. Again thanks for the help. Maybe someone will read this someday and post an answer. Bob p.