Crankshaft Position Sensor (CKP)
The Crankshaft Position Sensor (CKP) monitors the engine's crankshaft RPM. The ECU uses the Crankshaft Position Sensor's signal to monitor engine's rotational speed and calculate ignition timing advance and fuel injector timing advance.
Most common Honda engines use a crankshaft position sensor that is within the distributor housing. It is typically not available separately and must be replaced with the distributor housing.