Circuit/System Description

WARNING: This page is about a different car, the 2007 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.

The ignition system on this engine uses an individual module/coil for each cylinder. The engine control module (ECM) controls the spark event for each cylinder through the 8 individual ignition control (IC) circuits. When the ECM commands the IC circuit ON, electrical current will flow through the primary winding of the ignition coil, creating a magnetic field. When a spark event is requested, the ECM will command the IC circuit OFF, interrupting current flow through the primary winding. The magnetic field created by the primary winding will collapse across the secondary coil windings, producing a high voltage across the spark plug electrodes. The ECM uses information from the crankshaft position (CKP) sensor, and the camshaft position (CMP) sensor for sequencing and timing of the spark events. The ECM monitors each IC circuit for improper voltage levels. Each ignition module/coil assembly has the following electrical circuits:

An ignition voltage circuit
A ground
An IC control circuit
A low reference circuit