Module Communications Network

Module Communications Network

DESCRIPTION

Introduction
The diagnostic socket is located in the drivers footwell, and is constructed to SAE directive J1962. The socket allows T4 to interrogate and diagnose all control units connected to both the medium speed and high speed CAN bus. T4 can also communicate indirectly with electronic control modules indirectly via the instrument cluster.

OPERATION

Power Distribution
Feed from the positive battery terminal (C0192) is provided to fusible link 18E (C0632) on an R wire. Fusible link 18E is located in the Battery Junction Box (BJB) (C0570) and is connected to fuse 63P of the Central Junction Box (CJB) (C0583) by an NS wire. Fuse 63P (C0582) provides a constant battery feed to the diagnostic socket (C0040) on an LG wire. The diagnostic socket (C0040) is provided a ground path on a pair of B wires.

Diagnostic Socket
The diagnostic socket (C0040) is connected to all control units via the medium speed CAN bus on YU (high) and YW (low) wires. The diagnostic socket (C0040) is connected to all control units via the high speed CAN bus on YN (high) and YB (low) wires.

The diagnostic socket (C0040) is also able to communicate with the following:
^ The ABS module (C0506) on an R wire.
^ The Transmission Control Module (TCM) (C0193) on a GW wire.
^ The Restraints control module (C1649) on a P wire.