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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Information Bus: Description and Operation

Warning Classification And Behavior:





Check Engine
The CHECK ENGINE warning information is sent by the Electronic Engine Control (EEC) EEC-IV module on the Data Communication Link (DCL).

Check DCL
This warning is displayed when there is a fault in the DCL system. Anytime a CHECK ENGINE (MIL) warning occurs refer to Computers and Control, System Diagnosis. If a CHECK DCL warning occurs without a CHECK ENGINE warning, refer to DCL Quick Test for diagnosis of the DCL.