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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Engine Temperature Sensor: Description and Operation

This sensor/switch provides engine coolant temperature information to the ECM which uses this information to help determine when system is ready to enter closed loop mode as well as need for secondary air injection.