Nissan Repair: Speed sensor malfunction, nissan maxima, speed sensors

Question
I have a nissan maxima 1996. About a month ago check engine light came on. At Auto zone they told me that Speed sensor is malfunctioning.
I change the speed sensor but the check enging light is still on and the car failed emission test. code P0500. speed sensor malfunction
What should I do ?

Answer
Hi Seraphin,

There are two speed sensors on a transmission, input and output. If your speedo is working then it's the input speed sensor. A code P0500 is the output speed sensor. This should cause your speedometer to be in-op. If the speedometer works, you may have a bad computer. It's also called a pulse generator. If you replaced the right one, the one with a gear on it, and you still have no speedometer, then it's a short in the system. This happens a lot when someone installs a new stereo system and splices into that curcuit. Hope this helps...