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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Loop Status

OPEN LOOP/CLOSE LOOP
The Loop Status indicates when the VCM is controlling fuel delivery which is calculated using the HO2S bank 1 and 2 inputs. This is called closed loop fuel control. During open loop, the VCM ignores the HO2S input and bases fuel delivery upon TP, engine coolant, and MAF sensor input.