777G Off-Highway Truck Chassis Electronic Control System Caterpillar

Illustration 1	g02666176
Schematic of the Cat Data Link

This diagnostic code is recorded when the Advisor electronic control module (ECM) does not receive expected information from the VIMS Application ECM. The information is routed through the Cat Data Link. The information flow must be interrupted for more than 5 seconds for the diagnostic code to be active.

System Response:

This failure results in events that are logged against an ECM that cannot be explained directly. The Advisor ECM cannot communicate with the VIMS Application ECM or the VIMS Application ECM appears to communicate intermittently.

Test Step 1. VERIFY THE HARDWARE AND THE SOFTWARE PART NUMBERS.

1. Verify that the following information is correct:
   • The part number of the onboard software for the Advisor ECM

   • The part number of the flash software for the VIMS Application ECM

   • The part number of the Advisor ECM

   • The part number of the VIMS 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 Advisor ECM or the VIMS Application ECM has the wrong part number or the incorrect configuration software is installed. An Advisor ECM or the VIMS Application ECM with the wrong part number must be replaced with an ECM that has the correct part number. Prior to replacing an ECM, always contact the Technical Communicator for your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Section of this manual. Flash the correct configuration software. See the Testing and Adjusting, "Electronic Control Module (ECM) - Flash Program" Section of this manual.

  STOP

Test Step 2. INSPECT THE HARNESS CONNECTIONS.

1. Turn the disconnect switch to the OFF position.

2. Inspect all harness connections that are related to the Cat Data Link. Verify the following:
   • Connectors are clean.

   • Connectors are tight.

3. Check the connectors for proper mating. Ensure that all the seals are present and in place.

4. Check the harness for signs of damage or abrasion.

5. 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.

6. Check the exposed wires at the connectors for nicks or signs of abrasion.

7. Check for moisture inside the connector.

8. Check the connectors for dirty contacts or corroded contacts.

9. Check each pin and each socket of the machine harness connectors. Verify the following:
   • 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 or replace the machine harness.

  STOP

Test Step 3. CHECK FOR SHORTS TO GROUND

1. The disconnect switch remains in the OFF position.

2. Disconnect the machine harness from all electronic control modules that use the Cat Data Link.

3. At the machine harness for the Advisor ECM, measure the resistance between frame ground and connector contacts "8" (wire 893-GN) and "9" (wire 892-BR) of the Cat data link circuit.

Expected Result:

The resistance is greater than 5000 ohms.

Results:

• OK - The resistance is greater than 5000 ohms. The harness circuit resistance is correct. Proceed to Test Step 4.

• NOT OK - The resistance is less than 5000 ohms. The machine harness has failed.

  Repair: There is a short between frame ground and the Cat data link circuit in the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 4. CHECK FOR SHORT TO +BATTERY

1. The disconnect switch remains in the OFF position.

2. All related electronic control modules remain disconnected from the machine harness.

3. At the machine harness connector for the Advisor ECM, perform the checks that are listed here:
   • Measure the resistance between the +battery connector contact "J1-31" (wire 126-RD) and connector contact "8" (wire 893-GN).

   • Measure the resistance between the +battery connector contact "J1-31" (wire 126-RD) and connector contact "9" (wire 892-BR).

Expected Result:

The resistance is greater than 5000 ohms.

Results:

• OK - The harness circuit resistance is correct. Proceed to Test Step 5.

• NOT OK - The resistance is less than 5000 ohms. The machine harness has failed.

  Repair: There is a short between the +battery and the circuit for the Cat Data Link in the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 5. CHECK FOR OPEN HARNESS

1. The disconnect switch remains in the OFF position.

2. All related electronic control modules remain disconnected from the machine harness.

3. Check the continuity of the Cat Data Link in the machine harness:
   • Measure the resistance between connector contact "J1-10" (wire 893-GN) of the Advisor ECM and connector contact "8" (wire 893-GN) of the VIMS Application ECM.

   • Measure the resistance between connector contact "9" (wire 892-BR) of the Advisor ECM and connector contact "9" (wire 892-BR) of the VIMS Application ECM.

Expected Result:

The resistance measures less than 5 ohms.

Results:

• OK - The resistance is less than 5 ohms. The circuit for the Cat Data Link in the machine harness is correct. Proceed to Test Step 6.

• NOT OK - The resistance is greater than 5 ohms. The machine harness has failed.

  Repair: The circuit for the Cat Data Link is open in the machine harness. Repair the machine harness or replace the machine harness.

  STOP

Test Step 6. CHECK FOR ADDITIONAL DIAGNOSTIC CODES FOR THE OTHER ELECTRONIC CONTROL MODULES.

1. Reconnect all the electronic control modules that use the Cat Data Link.

2. Turn the disconnect switch and the key start switch to the ON position.

3. Check the event list for diagnostic codes that are logged against the other electronic control modules.

Expected Result:

Diagnostic codes are not present for the other electronic control modules in the event list.

Results:

• OK - Diagnostic codes are not present for the other electronic control modules in the event list.

  Repair: The VIMS Application ECM may have failed.A failure of the ECM is unlikely. Exit this procedure and perform this procedure again. Prior to replacing an ECM, always contact the Technical Communicator for your dealership for a possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Section of this manual.

  STOP

• NOT OK - Diagnostic codes are present for the other electronic control modules in the event list.

  Repair: The Advisor ECM may have failed.A failure of the Advisor ECM is unlikely. Exit this procedure and perform this procedure again. Prior to replacing an ECM, always contact the Technical Communicator for your dealership for a possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to the Testing and Adjusting, "Electronic Control Module (ECM) - Replace" Section of this manual.

  STOP