Ignition System: Description and Operation

Fig. 1 Spark Plug Cable Routing:

The PCM regulates the ignition system Fig. 1. The PCM supplies battery voltage to the ignition coil through the Auto Shutdown (ASD) Relay.

The PCM also controls the ground circuit for the ignition coil. By switching the ground path for the coil on and off, the PCM adjusts ignition timing to meet changing engine operating conditions.