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| Illustration 1 | g00894546 |
(1) CAT data link (2) CAN data link (3) Machine ECM (4) Engine ECM (5) Instrument panel (6) Service Connector | |
The machine has two data links: the CAT data link and the CAN data link. A data link is not a visible component. A data link consists of internal ECM circuits and the connecting harness wiring. Data links are bidirectional. Data links allow the ECM to receive information and data links allow the ECM to send information.
The CAT data link is an input and an output of the ECM. The CATdata link is connected to the ECM at connector J1-10 and J1-20. The machine ECM communicates with the engine ECM on the CAT data link.
The CAN data link is an input and an output of the ECM. The CAN data link is connected to the ECM at connector J2-67 and J2-68. The data link is designed to communicate with other electronic control modules through the machine harness. The machine ECM communicates with the engine ECM and the instrument cluster on the CAN data link. The engine ECM does not communicate directly with the instrument cluster. The engine information is sent to the machine ECM. Then, the machine ECM sends information to the instrument cluster.
Caterpillar Electronic Technician (ET) also communicates with other ECM modules through the data link. The ET will list the other ECM modules and the available diagnostic information. The information on both data links is available to the ET via the service connector.