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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General Description

The PCM processes the various input information. The PCM sends the necessary electrical responses to control fuel delivery, spark timing, and other emission control systems.

The input information has an interrelation to more than one output. One failed input can affect more than one Systems operation.