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| Illustration 1 | g00573691 |
The data link is an input and an output of the electronic control module (ECM). The data link is connected to the ECM at connector J1-7 and J1-8. The data link is designed to communicate with other electronic control modules through the machine harness. The data link is not a visible component. The data link consists of internal ECM circuits and the connecting harness wiring. The data link is bidirectional. The data link allows the ECM to receive information and the data link allows the ECM to send information.
The Transmission ECM requests the following information from the Brake ECM:
- The status of the service brake pressure
- The status of the secondary brake pressure
- The status of the park brake lockout
The Transmission ECM requests the following information from the Chassis ECM:
- The requested gear command
The Transmission ECM requests the following information from the VIMS ECM:
- The status of the machine payload overload
Caterpillar Electronic Technician (Cat ET) also communicates with other ECM modules through the data link. Cat ETwill list the other ECM modules and the available diagnostic information.
Note: All electronic control modules (ECM) that use the data link have a module identifier (MID). The MID is listed for each module:
Engine ECM (Front) ... 033
Engine ECM (Rear) ... 034
Engine ECM (Master) ... 036
VIMS Main Module ... 049
Transmission ECM ... 081
Chassis ECM ... 087
Brake/Cooling ECM ... 116