Ignition Coils
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Each ignition coil has an ignition 1 feed and a ground. The PCM supplies an ignition control (IC) circuit. Each ignition coil contains a solid state driver module as its primary element. The PCM signals the coil driver to initiate a firing event by applying the IC circuit voltage for the appropriate time or dwell. When the voltage is removed, the coil fires the spark plug. The coils are current-limited to prevent overloading if the IC current is held high too long. The spark plugs are tipped with platinum for long wear and higher efficiency.