Ignition Control Module: Description and Operation

The ignition timing is controlled by the Powertrain Control Module (PCM). The PCM detects information such as the injection pulse width and Camshaft Position (CMP) sensor signal which constantly varies. Then, responding to this information, an ignition signal is sent to the power transistor. The power transistor amplifies this signal and turns the ignition coil primary circuit on and off, inducing a high voltage in the secondary circuit. The power transistor is located between the distributor and the ignition coil.