Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Ignition Control Module: Description and Operation

Ignition Control Module:

The Ignition Control Module (ICM) with Computer Control Dwell (CCD), and the Powertrain Control Module (PCM) control the ignition coil charge timing.

The Ignition Diagnostic Monitor (IDM) is a function of the ICM. The ICM sends information on system failures to the PCM which stores the information for diagnostic self tests. The IDM signal also is used to drive the tachometer.