2004 Nissan Maxima computer problems

Twice, when the engine has reached its maximum temperature, the transmission has become stuck in 5th gear (which I can tell after I stop and shift to the manual override). After it cools down and is restarted, it drops back to normal. The first time, a mechanic read the code "input speed sensor" (also called "turbine control" I think) and replaced it. Two days later, on the second time, the "traction control off" light came on. When checked, we got two codes, "camshaft position sensor A circuit (Bank 1 or Single Sensor)" and "engine cutback system on." The codes were cleared, nothing else was done, and now it is running normal again. Two questions: 1) do I risk doing damage by driving it; 2) what needs to be done if it happens again? Many thanks, Mark