TUBE 2941830 - Caterpillar

Illustration 1 g02793473
RS-485 network
This diagnostic code is recorded if the VIMSTM 3G Application ECM detects an abnormal update rate from the RS-485 data-link.System Response:This failure results in events that are logged to the VIMS 3G Application ECM that cannot be explained. The VIMS 3G Application ECM cannot communicate correctly with the RS-485 data-link.Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS
Verify that the following part numbers are correct:
VIMS 3G Application ECM software
VIMS 3G Application ECM Note: For the correct part numbers, consult the product business unit.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: Replace the incorrect VIMS 3G Application ECM with an ECM that has the correct part number. See Testing and Adjusting, "Electronic Control Module (ECM) - Replace". Flash the correct software. See Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program".STOPTest Step 2. INSPECT THE HARNESS
Turn off the disconnect switch.
Inspect all connections related to the RS-485 data- link.
Inspect the connectors, pins, and sockets for the following:
Cleanliness
Security
Proper mating
Seal condition
Moisture
Corrosion
Inspect the wires at the connector for the following:
Security
Nicks
AbrasionNote: Take care not to pull the wire out of the connector.
Inspect the harness for the following:
Damage
Abrasion
KinksExpected Result:The harness is in good condition.Results:
OK - The harness is in good condition. Proceed to Test Step 4.
NOT OK - The harness is not in good condition.Repair: Repair or replace the harness. STOPTest Step 3. CHECK THE 120 OHM TERMINATING RESISTORSThe disconnect switch remains off.
Disconnect all of the VIMS 3G ECMs from the RS-485 data-link.
At the VIMS 3G Application ECM harness, measure the resistance between the following:
Contact 4 (939-WH(White)) and contact 5 (940-BU(Blue))
Contact 17 (920-BR(Brown)) and contact 18 (921-YL(Yellow))Expected Result:The resistance is approximately 60 ohms. Results:
OK - The resistance is approximately 60 ohms. Proceed to Test Step 5.
NOT OK - The resistance is not approximately 60 ohms. The harness or the terminating resistor has failed. Repair: Repair or replace the harness, or replace the terminating resistor. STOPTest Step 4. CHECK FOR SHORTS TO GROUNDThe disconnect switch remains off. VIMS 3G ECMs remain disconnected from the RS-485 data-link.
At the VIMS 3G Application ECM harness, measure the resistance between frame ground and the following:
Contact 4 (939-WH(White))
Contact 5 (940-BU(Blue))
Contact 6 (969-GY(Grey))
Contact 17 (920-BR(Brown))
Contact 18 (921-YL(Yellow))Expected Result:The resistance is greater than 5000 ohms. Results:
OK - The resistance is greater than