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 Control Switch (on/Off)


Displays status of ECM signals to air cleaner divert and air switching solenoids. With air cleaner divert signal in off condition, air pump output should be routed to atmosphere. In the on position, air pump output should be routed to the air switching solenoid. When the air divert solenoid is on and the air switching solenoid is on, air should be delivered to the exhaust ports. When the divert solenoid is on and the switching solenoid is off, air should be delivered to the catalytic converter.