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)

Or, hide this message: temporarily or permanently

Information Bus: Description and Operation

[1][2]DATA LINK COMMUNICATIONS DESCRIPTION AND OPERATION

The scan tool accesses the following data lines:
^ The Brake Pressure Control Valve (BPMV), on vehicles with antilock brake systems
^ The Powertrain Control Module (PCM)

The WHT wire at cavity 7 of the Data Link Connector (DLC) OBD 2 provides access to the BPMV and to the PCM. The RED wire at cavity 16 provides voltage to the scan tool. The WHT/BLK wire at cavity 4 and the BRN wire at cavity 5 provides ground to the scan tool.

The data lines monitor the module for diagnostic purposes and for Diagnostic Trouble Codes (DTCs).