RING 7D4715 - Caterpillar

Operation Description:During the installation of a Product Link 321 system, the wiring harness is connected to the existing machine Cat® data-link wiring. If connection is not done properly, the continuity of the Cat data-link wiring may be intermittently open. This condition may not be immediately apparent and will cause a problem when connecting the Caterpillar® Electronic Technician (Cat ET) service tool to the machine.
Cat ET may report that no ECM has been found.
Cat ET may not report every ECM that is on the machine.
Cat ET may report an ECM, but the ECM will not have any data.If the Cat data-link wires are reversed during the installation, the Product Link ECM will not be shown after connecting Cat ET to the machine.Test Step 1. VERIFY THAT THE CAT® DATA-LINK WIRES ARE NOT REVERSED
Check that the positive Cat data-link (CDL+) wire (893-GN) in the harness is connected to the CDL+ wire (893-GN or 944-OR) of the harness.
Check that the negative Cat data-link (CDL-) wire (892-BR) in the harness is connected to the negative Cat data-link (CDL-) wire (892-BR or 945-BR) of the harness.Expected Result:The Cat data-link wires are properly connected.Results:
OK - The Cat data-link wires are properly connected. Proceed to Test Step 2.
NOT OK - The Cat data-link wires are reversed.Repair: Reinstall the Cat data-link wires and check the Product Link ECM operation with Cat ET. STOPTest Step 2. CHECK THE HARNESS WITH A MULTIMETER
Turn off the machine.
Turn the disconnect switch to the OFF position.
Measure the resistance of the negative Cat data-link wire from the service connector (contact "E") to the location for the spliced Cat data-link wire. Note the resistance.
Measure the resistance of the positive Cat data-link wire from the service connector (contact "D") to the location for the spliced Cat data-link wire. Note the resistance.Expected Result:The resistance in both wires is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. Proceed to Test Step 3.
NOT OK - The resistance is greater than 5 ohms. The harness has failed.Repair: Repair or replace the harness. After repairing or replacing the harness, resume the Product Link setup procedure.STOPTest Step 3. VERIFY THAT THE CAT DATA-LINK WIRING IS PROPERLY CONNECTED
Check the Cat data-link spliced connections that were made during the installation. Verify that all connections are clean and tight.
Reconnect the harness connectors that were disturbed during the installation. Ensure that all of the pins are correctly seated in the sockets.
Reconnect the cable from the service tool connector. Attempt to access the Cat data-link with Cat ET.Expected Result:Cat ET lists the available ECMs. The Product Link ECM can be accessed.Results:
OK - Cat ET lists the available ECMs. The Product Link ECM can be accessed. Resume the Product Link setup procedure.STOP
NOT OK - The Cat ET does not list the available ECMs. The Product Link ECM cannot be accessed. Proceed to Test Step 4.Test Step 4. CHECK FOR A MONITORING SYSTEMCheck if the machine is equipped with a monitoring system. Some common monitoring systems include the following systems:
Electronic monitoring system
Computerized monitoring