966G Wheel Loader and 972G Wheel Loader Power Train Caterpillar

The CAT Data Link is a communication link that is used for the movement of data between electronic controls. The CAT Data Link allows communication between the power train electronic control module (ECM) and the Caterpillar Monitoring System. The CAT Data Link is bidirectional. The CAT Data Link allows the power train ECM to input information. The CAT Data Link allows the power train ECM to output information. The CAT Data Link is not a visible component. The CAT Data Link consists of the following parts: internal circuits of the power train ECM, the related harness wiring and the service tool connector. The CAT Data Link and the power train ECM are connected at pin-out J1-3 and pin-out J1-9.

The power train ECM and the Caterpillar Monitoring System use data that is sent back and forth on the CAT Data Link. The following information is some of the information that is shared:

• The power train ECM receives service commands from the Caterpillar Monitoring System in order to change the operating modes of the power train electronic control system. The service commands can direct the power train ECM to read service codes that are stored in the memory of the power train ECM. The service commands can direct the power train ECM to clear service codes that are stored in the ECM memory.

• The power train ECM receives the harness code input from the Caterpillar Monitoring System. The power train ECM determines the sales model of the machine from the harness code input.

• The power train ECM sends signals to the Caterpillar Monitoring System. The Caterpillar Monitoring System uses the signals to report on the status of the power train electronic control system. The Caterpillar Monitoring System alerts the operator of the status by illuminating the corresponding alert indicator.

• The power train ECM sends the information that follows to the Caterpillar Monitoring System: parking brake status, transmission direction status and transmission speed status. The Caterpillar Monitoring System displays the transmission direction that is selected and the transmission speed that is selected. The Caterpillar Monitoring System uses this information in order to show the operator if the parking brake is engaged or disengaged.

Note: All electronic control modules that use the CAT Data Link have a module identifier (MID). The module identifiers that follow are valid for the machines that are the subject of this service manual module:

Module Identifiers (MID)

Power Train Electronic Control System ... 081

Caterpillar Monitoring System ... 030

Implement Electronic Control System ... 082

Reference: For more information on the Caterpillar Monitoring System, refer to the Service Manual module Systems Operation, "Monitoring System (Power Train Functions)" for the machine that is being serviced.

Reference: For more information on the power train electronic control module (ECM), refer to the Service Manual module Systems Operation, "Electronic Control Module (Power Train)" for the machine that is being serviced.