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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Idle Air Control

PURPOSE
Maintains the proper idle speeds during warm-up and with different engine loads.

OPERATION
When the engine is cold, the A/C compressor is on, the transmission in gear (A/T only) or the alternator is charging, the Engine Control Module (ECM) controls current to the Idle Air Control (IAC) valve to maintain correct idle speed by introducing more air into the intake manifold.