Camshaft Sensor(s)
WARNING: This page is about a different car, the 1997 Lexus SC 300. However, it is still accessible from the selected car via links, so may be relevant.
The camshaft sensor contains a pick-up coil. A signal plate (rotor) is mounted on the camshaft. As the camshaft rotates, a protrusion on the signal plate passes near the pick-up coil. This induces AC voltage in the pick-up coil. The ECM senses AC voltage, and interprets it as camshaft position.