Operation CHARM: Car repair manuals for everyone.
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

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

IC Mode

Display shows PCM or ICM. In PCM mode, the PCM controls the ignition timing. The PCM calculates the desired ignition timing based on information the PCM receives from the input sensors. In Ignition Control Module (ICM) mode, the ignition system operates independently from the PCM. The Ignition Control Module maintains a base ignition timing of 10 degrees BTDC and is able to change this ignition timing slightly with increased engine speed. Ignition control mode is in affect whenever an ignition control fault is detected while the engine is running and it will have a noticeable effect on driveability.