FILM GP 4239797 - Caterpillar

Illustration 1 g02153694
Schematic of the RS-485 networkThis diagnostic code is recorded if the VIMS 3G Application ECM has detected an abnormal update rate from the RS-485 communication.System Response:This failure results in events that are logged to the VIMS 3G Application ECM that cannot be explained directly. The VIMS 3G Application ECM cannot communicate correctly with the RS-485 .Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS.
Verify that the following information is correct:
The part number of the VIMS 3G Application ECM onboard software
The part number of the VIMS 3G Application ECM Note: Consult the Business Unit that produces the product for the correct part numbers of the configuration software.Expected Result:All part numbers are correct. Results:
OK - All part numbers are correct. Proceed to Test Step 2.
NOT OK - All part numbers are NOT correct.Repair: The installed VIMS 3G Application ECM has the wrong part number or the incorrect configuration software is installed. Replace the incorrect VIMS 3G Application ECM with an ECM that has the correct part number. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Flash the correct configuration software. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program".STOPTest Step 2. INSPECT THE HARNESS CONNECTIONS.
Turn the disconnect switch OFF.
Inspect all harness connections that are related to the RS-485 circuit. Make sure that the connectors are clean and tight.
Check the connectors for proper mating. Ensure that all the seals are present and in place.
Check the harness for signs of damage or abrasion.
Check the wires at the connector. Ensure that the wires are secured tightly into the connector. Take care not to pull the wire out of the connector.
Check the exposed wires at the connectors for nicks or signs of abrasion.
Check for moisture inside the connector.
Check the connectors for dirty contacts or corroded contacts.
Check each pin and each socket of the machine harness connectors. Ensure that the contacts are properly installed. The contacts should mate correctly when the two pieces of the connector are placed together. Expected Result:The machine harness connectors are tight and free of corrosion. Results:
OK - The machine harness connectors are tight and free of corrosion. Proceed to Test Step 4.
NOT OK - The machine harness connectors are in need of repair.Repair: Repair the machine harness or replace the machine harness. STOPTest Step 3. CHECK THE 120 OHM TERMINATING RESISTORS
The disconnect switch remains in the OFF position.
Disconnect both of the VIMS ECM from the RS-485 circuit.
At the machine harness for the VIMS 3G Application ECM, measure the resistance between connector contacts that follow:
Contact 17 (939-WH) and Contact 18 (940-BU)
Contact 4 (920-BR) and Contact 5 (921-YL)Expected Result:The resistance is approximately 60 ohms. Results:
OK - The resistance is approximately 60 ohms. The terminating resistors are correct. Proceed to Test Step 5.
NOT OK - The resistance is not approximately 60 ohms. The machine harness has failed or the terminating resistor has failed. Repair: Repair the machine harness or replace the terminating resistor. STOPTest Step 4. CHECK FOR SHORTS TO GROUND
The disconnect