Trouble code P0500 indicates your Nissan's Vehicle Speed Sensor (VSS) is not working properly. This problem will illuminate the Check Engine Light and set a trouble code within the ECU.
Since the required repair of replacing the Speed Sensor was performed you must now ensure the trouble codes have been erased and do not reappear.
The additional repairs you've conducted appear to be maintenance related and are always recommend.
We can only recommend you drive your Nissan Xterra for at least 2 weeks prior to getting a retest.
posted by SmogTips Support