Medium Speed Controller Area Network (CAN)

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The medium speed CAN is an unshielded twisted pair cable using data plus circuit VDB06 (GY/OG) and data minus circuit VDB07 (VT/OG). The medium speed CAN is not designed to operate under single point fault conditions. If either circuit is shorted to voltage or the medium speed CAN data plus is shorted to ground, module-to-module and module-to-tester communication is not possible. If the medium speed CAN data minus is shorted to ground or an open exists on either bus line, module-to-module and module-to-tester communication is marginal at best.

There are 2 terminating modules on the medium speed CAN, which are the smart junction box (SJB) and the instrument cluster located at the far opposite ends of the medium speed CAN wiring. The high speed CAN bus may remain operational when one of the two termination resistors are not present. If there are issues with the medium speed CAN, there may be missing functionality and problems connecting with a diagnostic tool.

The termination resistors are internal components to the module. If a module's termination resistance is found to be the cause of the medium speed CAN network fault, a new module must be installed.