SPRING 2V7440 - Caterpillar

Conditions Which Generate This Code:
Illustration 1 g01257797
Schematic of the J1939 Data LinkThe diagnostic trouble code is associated with the Transmission ECU. The FMI 9 means that the ECU is not receiving any of the expected information from the data link.The possible causes of this diagnostic trouble code are listed if only two ECUs cannot communicate:
Loose harness connections
Open wires
Problems with the terminating resistors
Wires that are shorted to ground
Wires that are shorted to the battery
Data link high wire is shorted to the data link low wire
High resistance across the Data Link
Interference across the wires for the Data Link
Incompatible Software
Incorrect set up for parameter
Failure of a smart device
The ECU has failed. This is unlikely.The possible causes of this diagnostic trouble code are listed if all of the ECUs cannot communicate:
Problems with the terminating resistors
Wires that are shorted to ground
Wires that are shorted to the battery
Data Link high wire is shorted to the Data Link low wire
Interference across the wires for the Data LinkNote: The high and the low wires of the data link have a positive voltage. One does not have a negative voltage. The shield wire should not be used as a ground wire when the voltage is measured. Always use a clean, unpainted connection to the frame ground. The Caterpillar Electronic Technician, Cat ET, may show a controller to be off-line. The controller may not have been recognized by Cat ET. Cycling the key and restarting the Cat ET may correct the problem.Test Step 1. INSPECT THE HARNESS CONNECTIONS.
Turn the disconnect switch to the OFF position.
Inspect all of the harness connections. 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. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit. 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. Note: See Testing and Adjusting, "Electrical Connector - Inspect" for more information.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 2.
NOT OK - The machine harness connectors are in need of repair.Repair: Repair the machine harness or replace the machine harness. Proceed to Test Step 8.Test Step 2. CHECK THE VOLTAGE OF THE DATA LINK.
Turn the keyswitch and the disconnect switch to the ON position.
At the ECU, use an electrical spoon to measure the voltage. One at a time, measure the voltage of connector contact J1-67,