Crankshaft sensor on a 2000nissan xterra where is it located and how can it be replaced

Crankshaft position sensor location for 3.3 V6 engine is mounted at the rear of the engine on transmission bellhousing, the 3.5 V6 engine crankshaft sensor located at front of the engine on the aluminum oil pan section below crankshaft pulley.replace the crankshaft position sensor remove heat shield disconnect the electrical connector the remove sensor retaining bolt then remove crankshaft sensor.after replacing crankshaft sensor you need to erase code if check light come back on.