2012 Honda civic lx where's crankshaft position sensor location

You often do not need a new crankshaft position sensor. You could have a wiring issue or another problem. Following proper troubleshooting procedures to get to the bottom of the problem is the best course of action. The sensor, in case you feel like replacing it anyway, is under the front of the vehicle. The lower engine pan must be removed for access, and it will be on the bottom of the engine. Yes, you will need a diagnostic tool to perform a learning procedure.