When replacing the crankshaft sensor on 2005 and older models, or when installing the crankshaft pulley on 2000 and later models, the PCM must be reprogrammed using specialist equipment, which must be done by authorized dealer technicians or qualified repair shops. The two CKP sensors are installed on top of the block, near the oil filter, one directly above the other. Start your work by taking off the cable from the car's battery negative terminal. When ready, lift up the front of the car and carefully set it on jackstands. Follow these steps to remove a CKP sensor-pull out the electrical connector and loosen the bolt that holds it down while you have two CKP sensors to deal with-the "A" CKP sensor can be unplugged and has its screw removed, whereas the "B" CKP sensor, which sits above the "A" sensor is taken off in exactly the same way. Loosen the CKP sensor bolt, then pull the sensor out of its place. Check the CKP sensor O-ring for damage, then replace it if cracks or tears are found. Before putting the new O-ring inside, soak it in clean engine oil first. Soak the new O-ring with cleans oil, then put it on the CKP sensor. To finish, reverse what you did in removal-tighten the CKP sensor retaining bolt at the specified torque level.