Information Bus: Description and Operation
There are two data lines that can be accessed with a scan tool. The 461 circuit data line is the PCM Data Line. It allows the Powertrain Control Module (PCM), and Electronic Brake Control Module (EBCM) (if equipped) to communicate by transmitting data through CKT 461.
A scan tool can be connected to the DLC; this allows the scan tool to communicate with the PCM Data Line. System operations can then be monitored for diagnostic purposes.