Ignition Control Module: Description and Operation

DESCRIPTION AND OPERATION

Ignition Control Module:

The ignition control module (ICM) receives the Crankshaft Position Sensor (CKP) signal from the CKP sensor. The ignition control module will use the CKP signal to synchronize the ignition coils for the proper spark timing sequence and to create the Profile Ignition Pickup (PIP) signal. The PIP signal is sent to the Powertrain Control Module (PCM) where it will be used for base ignition timing calculations and crankshaft speed (RPM) calculations. The ignition control module will also receive the Spark Output (SPOUT) signal from the PCM. The ignition control module will use the SPOUT signal to calculate the proper spark timing advance. When all the signals are calculated, the ignition control module will determine the proper ON and OFF time of the ignition coils for spark delivery.

Failure Mode Effects Management
During some electronic ignition (EI) system faults, the Failure Mode Effects Management (FMEM) portion of the ICM will maintain vehicle operation. If the ignition control module does not receive the SPOUT input, it will automatically turn the ignition coils ON and OFF using the CKP signal. However, this condition will result in fixed spark timing (10 degrees BTDC).

Ignition Diagnostic Monitor
The Ignition Diagnostic Monitor (IDM) is a function of the ICM. The ignition control module sends information on system failures to the PCM, which stores the information for use in Diagnostic Test Mode. The IDM signal is also used to drive the vehicle instrument tachometer.