TUBE AS-DRAIN 8N4940 - Caterpillar

Illustration 1 g02292316
Schematic of the J1939 Data LinkThis diagnostic code is caused by abnormal communications between the Machine ECM and the "Monitor Display" ECM through the Data Link. The update rate is not correct. Check if a diagnostic code that is related to the data link of the machine or the "Monitor Display" ECM is present. If a diagnostic code is present, correct the related diagnostic code.A possible cause of this diagnostic code is listed below:
The Machine ECM is operating intermittently.The Data Link is an input and output of all electronic control modules. The data link is designed to carry communications between the electronic control modules. The data link is not a visible component. The data link consists of internal control circuits and the connecting harness wiring. System Response:This failure results in events that are logged against an ECM that cannot be explained directly. The Machine ECM cannot communicate with this ECM or the ECM appears to communicate intermittently. Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS.
Verify that the following information is correct:
The part number of the flash software for the Machine ECM
The part number of the flash software for the "Monitor Display" ECM
The part number of the machine ECM
The part number of the "Monitor Display" ECMNote: Consult your Caterpillar Authorized Dealer for the correct part numbers of the flash software.Expected Result:All of the part numbers are correct. Results:
OK - All of the part numbers are correct. Proceed to Test Step 2.
NOT OK - All of the part numbers are not correct. Repair: The installed Machine ECM or the "Monitor Display" ECM have the wrong part number or the incorrect flash software is installed. Replace the incorrect Machine ECM or the "Monitor Display" ECM with a module that has the correct part number. Flash the correct software. See the Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program" section for additional information.STOPTest Step 2. INSPECT THE HARNESS CONNECTIONS.
Turn the disconnect switch to the OFF position.
Inspect all harness connections that are related to the J1939 Data Link. 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 3.
NOT OK - The machine harness connectors are in need of repair.Repair: Repair the machine harness