Circuit Description

When distributor shaft rotates, a fluctuating magnetic field is generated due to changes in air gap between Camshaft Position (CMP) sensor and distributor shaft signal rotor. As a result, a small AC voltage is induced in CMP sensor. This ignition reference signal is sent to PCM. PCM uses this signal in determining engine speed and when to fire ignition coil and fuel injector. DTC P0340 will set when no CMP sensor signal is generated with engine cranking for at least 2 seconds.