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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ISU (Intelligent Switching Unit)

ISU (Intelligent Switching Unit)

ISU is installed on the left side of the steering column in side the instrument panel. ISU processes signals from the remote transmitter and the intrusion sensors, and it activates the alarm if an invasion is detected.
The ISU also has a self-diagnostic functions which will display trouble codes. In order to display trouble coeds, a scan tool must be connected to the Data Link Connector (DLC).
The ISU will not communicate with transmitters from other vehicles because there are over four billion possible electronic password combinations. The ISU has an attached antenna to detect signals from the transmitter.