Ignition Coil: Description and Operation

The ignition coil, which is mounted on the upper intake manifold, can be described as a coil pack containing three separate coil units. Each coil unit is individually controlled by the Powertrain Control Module (PCM) through separate wire leads. Each coil unit activates two spark plugs wired in a series by the spark plug wires.
- One spark plug activates on the compression stroke and uses the majority of the ignition coil's stored energy.
- The other spark plug activates on the exhaust stroke and uses very little of the ignition coil's stored energy.
- Because the pairs of spark plugs are connected in a series, one spark will travel from ground to the electrode while the other spark will travel from the electrode to ground.