Ignition Control Module: Description and Operation

IGNITION CONTROL MODULE (ICM) AND IGNITION COILS

Three dual tower ignition coils are mounted to the ICM and are serviced individually. The ICM performs the following functions:
- The ICM receives and processes the signals from the 7X CKP sensor.
- The ICM determines the correct direction of the crankshaft rotation, and cuts spark and fuel delivery to prevent damage from backfiring if reverse rotation is detected.
- The ICM determines the correct coil triggering sequence, based on the 7X CKP signal. This coil sequencing occurs at start-up, and is remembered by the ICM. After the engine is running, the ICM will continue to trigger the coils in the correct sequence.
- The ICM produces and inputs 3X reference signals to the PCM.
- The ICM contains the coil driver circuits that command the coils to operate.