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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A/C Request Signal

The ECM is signaled by the A/C relay whenever the A/C is turned on. The ECM then responds by modifying the duty cycle to the idle stabilizer valve, increasing the idle speed by approximately 100 rpm. This is to ensure a smooth idle with the additional load of the A/C compressor, as well as to ensure more efficient A/C operation when the engine is idling.

PLAUSIBILITY CHECK

There is no self diagnosis or substitute signal for this input.