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

Air Switch-Air Control Solenoid


This switch can be used to check for proper operation of the AIR system by directing air to the exhaust ports to test effect on readings such as the O2 sensor voltage or MC solenoid dwell. When activated, the solenoid remains energized for up to 20 seconds. After 20 seconds, a timer energizes the solenoid to prevent heat damage to the catalytic converter.