Nissan Repair: Crankshaft position sensor malfunction, crankshaft position sensor, crankshaft sensor

Question
My check engine light came on my 1996 Nissan Altima and the codes were knock sensor and crankshaft position sensor malfunction.  I replaced the knock sensor even though they are not neccessary because I am selling the car and I don't want the light on.  I waited on the crankshaft position sensor because my mechanic told me to see if after resetting the check engine light it would stay off.  It did, for one day.  I have found a crankshaft sensor for about $32.  My only worry is that I have read on the Nissan Forum about the teeth being bent or something that causes the sensor to trigger a malfunction.  Is there a reason that they went out at the same time, and should I replace the sensor or just forget about it or disconnect it?

Answer
Phillip,

Change the sensor as it will continue to set the check engine light and you do nto want someone coming back on you after you sell it.  The problem is with the sensor and not the teeth.  The sensor is basically a hall effect sensor that senses when ferrite metal passes it.  The teeth they are talking about are these and that is what tells the computer when to fire the plugs and injectors.  So, it is vital that it work properly for the car do function correctly.  You could say Mean Time Between Failures (MTBF) on the sensors going out at the same time.  Manufacturers work to get things to last for just so long and some of them have it down to a science.