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)

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Electronic Spark Advance

This signal is sent from the igniter. ECM uses it as one of the signals for controlling fuel injector. Monitoring this signal, ECM detects whether the ignition spark is emitted or not and stops injector operation when this signal is not inputted.