Operation CHARM: Car repair manuals for everyone.
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Information Bus: Description and Operation

There are two data lines that can be accessed with a scan tool. The 800 circuit data line is the Powertrain Control Module (PCM) Data Line. It allows the PCM, Diagnostic Energy Reserve Module (DERM) and Electronic Brake Control Module (EBCM) to communicate by transmitting data through CKT 800. The 835 circuit data line is the Entertainment and Comfort (E & C Bus) Data Line. It allows the Radio and Radio Control Interface Module to communicate via CKT 835.
A scan tool can be connected to the Data Link Connector (DLC); this allows the scan tool to communicate with both the PCM Data Line and E & C Data Lines. System operations can then be monitored for diagnostic purposes.

Security Indicator
The Theft Deterrent Module will produce a switched ground signal when a fault in the Theft Deterrent System is detected and also when the vehicle is being started as a bulb check. For diagnosis refer to Theft Deterrent System. Antitheft and Alarm Systems