Camshaft Position Sensor

The PCM uses Camshaft Position (CMP) sensor input to determine injector and spark timing. The CMP sensor is located in the distributor. The CMP sensor uses a photo sensor and slotted disc, mounted inside the distributor.

The slotted disc rotates with the distributor shaft. The slotted disc has 360 slots for one degree signal and 6 slots for 120 degree signals. When the slot passes through the photo sensor, an input signal is generated and sent to the PCM. Using this information, the PCM calculates camshaft position and engine speed. This signal affects air/fuel ratio, ignition timing and emissions.