Crankshaft Position (CKP) Sensor
WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2000 Nissan Xterra, 2000 Nissan Sentra, 2000 Nissan Quest, 2000 Nissan Pathfinder, and 2000 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
All models are equipped with one CKP sensor (POS) located at rear of engine, facing flywheel. CKP sensor monitors engine speed and piston position. Maxima models are equipped with a second CKP sensor (REF) that is mounted at front of engine near oil filter. This CMP sensor detects engine compression TDC signal.
CKP sensors consists of a permanent magnet, core and coil. When engine is running, gap between sensor and flywheel teeth (POS) or crankshaft pulley (REF) will periodically change. Voltage signal generated in coil is sent to ECM, which detects crankshaft position or compression TDC signal.