Mine had the same code a while back. I too, installed a new sensor to no avail. Turns out, the darned thermostat was broken in two at the factory rivets holding the top & bottom pieces together. The center shaft holding the disc was bent roughly 10 degrees off center!

Go down the road and note the behavior of the temperature indicator. Replace the thermostat if the needle fluctuates with respect to engine load. In other words - ascending a long steep grade, does the needle climb? Likewise, going downhill, does it drop?? Heck, just replace the thing. Took 30 minutes at the most.