773G and 775G Quarry Trucks Chassis Electronic Control System Caterpillar

SAE J1939 DATA LINK

Illustration 1	g02665058
Connections of the SAE J1939 data link circuit

SAE J1939 Data Link

The CID 0247 FMI 09 diagnostic code is used by the "Chassis ECM" as a "companion code". The companion code is activated simultaneously with a diagnostic code from another control module. The above mentioned diagnostic codes indicate that the SAE J1939 Data Link has an abnormal condition.

The possible causes of the CID 0247 FMI 09 diagnostic code are listed below:

• Terminating resistors on the J1939 Data Link are faulty

• An open or a poor connection in the data link circuit

• Short in the data link circuit

• An ECM or smart device is not powering up or powering down properly

• Lack of key switch input to an ECM or smart device (where applicable)

• Excessive noise on the data link circuit

• Software configuration mismatch

• One of the ECM modules has failed. This condition is unlikely.

The FMI 09 code will match the FMI 09 code that is activated for the diagnostic code of the control module. The FMI 09 means that the "Chassis ECM" has lost all communication with the other control module.

The CID 0247 FMI 09 diagnostic code will never be activated by the "Chassis ECM" as a stand-alone diagnostic code. The "Chassis ECM" will only activate the CID 0247 FMI 09 diagnostic code along with one of the following module communication codes.

• CID 0590 FMI 09

• CID 1089 FMI 09

For example, if the "Chassis ECM" detects that no communication is being received from the Engine ECM over the SAE J1939 Data Link, the "Chassis ECM" will simultaneously activate a CID0590 FMI 09 (Engine ECM) diagnostic code and a CID0247 FMI 09 (SAE J1939 Data Link) diagnostic code.

If the "Chassis ECM" did not activate the companion diagnostic code CID 0247 FMI 09 along with the control module code, the technician would not know which data link circuit (Cat Data Link or J1939 Data Link) is involved.

When the CID 0247 FMI 09 diagnostic code is activated by the "Chassis ECM", always look for one of the control module diagnostic codes that are listed above in order to troubleshoot the problem.

Note: A loss of power in the system to an ECM can cause the Chassis ECM to activate this diagnostic code. Ensure that the ECM modules with this diagnostic code are powered up before proceeding with this procedure.

Perform the following procedure when the CID 0247 FMI 09 diagnostic code is activated. Verify that the CID 0247 FMI 09 diagnostic code is active before performing this procedure.

Test Step 1. INSPECT THE HARNESS CONNECTIONS

1. Turn the disconnect switch to the OFF position.

2. Inspect all of the harness connections. Make sure that the connectors are clean and 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. 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.

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. 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 7.

Test Step 2. CHECK THE VOLTAGE OF THE DATA LINK

1. Turn the keyswitch and the disconnect switch to the ON position.

2. Connect CAT ET and verify which ECM modules have communication diagnostics against them. At all the ECM modules or devices that are not communicating, use an electrical spoon to measure the voltage. One at a time, measure the voltage of connector contact J1-67, J1-68, and J1-69 to frame ground.

   Note: Do not use the shield wire as a ground.

   Show/hide table

   Table 1

   J2-67	J2-68	J2-70
   0.5V to 4.5V	0.0V	0.0V

Expected Result:

The shield wire does not have a voltage. A voltage on the shield wire means that there is a short to the battery. The voltage of the wires for the Data Link is correct.

Results:

• OK - The voltages of the wires for the Data Links are correct. Proceed to Test Step

• NOT OK - The voltage is greater than 4.5 V.

  Repair: Repair the machine harness or replace the harness.

  Proceed to Test Step 7

• NOT OK - The voltage is less than 0.5 V. Proceed to Test Step 3.

Test Step 3. CHECK FOR A SHORT TO GROUND

1. Turn the keyswitch and the disconnect switch to the OFF position.

2. Disconnect the J2 harness connector for one of the ECM modules.

3. Measure the resistance of wire (F711-YL) to an unpainted frame ground. Measure the resistance of wire (F712-GN) to an unpainted frame ground.

Expected Result:

The resistance measurement is greater than 5000 ohms.

Results:

• OK - The resistance measurement is correct. Proceed to Test Step 4.

• NOT OK - The resistance measurement is not correct. The wire with the low resistance measurement is shorted to ground.

  Repair: Repair the machine harness or replace the machine harness.

  Proceed to Test Step 7.

Test Step 4. CHECK FOR A SHORT IN THE WIRES FOR THE DATA LINK.

1. The keyswitch and the disconnect switch remain in the OFF position.

2. Disconnect the terminating resistors if the resistors are a part of the circuit.

3. Measure the continuity between the data link wires.

Expected Result:

The resistance measurement is greater than 5000 ohms.

Results:

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

• NOT OK - The resistance measurement is not correct. The wires for the data link are connected.

  Repair: Repair the machine harness or replace the machine harness.

  Proceed to Test Step 7.

Test Step 5. CHECK THE TERMINATING RESISTORS

1. The keyswitch and the disconnect switch remain in the OFF position.

2. The terminating resistors remain disconnected.

3. Check the terminating resistor connectors for the following:
   • Moisture

   • Corrosion

   • Damaged terminals

   • Loose connections

4. Measure the resistance between terminal A and B of each terminating resistor that was removed from the CAN circuit.

Expected Result:

The resistance measurement is approximately 120 ohms.

Results:

• OK - Both resistance measurements are approximately 120 ohms. The terminating resistors have not failed. Reinstall the terminating resistors. Proceed to Test Step 6.

• NOT OK - The resistance measurement is not approximately 120 ohms. One of the resistors is not functioning properly.

  Repair: Replace the terminating resistor that has failed.

  Proceed to Test Step 7.

Test Step 6. CHECK THE HARNESS.

Note: Two 120 Ohm resistors should be located on the CAN Data Link. A resistance of 60 ohms should be found at any point on the data link.

1. The keyswitch and the disconnect switch remain in the OFF position.

2. Use an electrical spoon to connect to the back of the harness connector for each ECM that has communication issues.

3. Measure the resistance across the CAN line at each connector in order to find the open wire. If the resistance measurement is 60 ohms, that connector does not have an open between either terminating resistor. If the resistance measurement is 120 ohms, there is an open wire on one of the CAN lines at that connector between one of the terminating resistors. If the resistance is greater than 5000 ohms, there is an open between that connector and both terminating resistors. If there is a measurement of 40 ohms, there is an extra terminating resistor somewhere on the line. Once the part of the harness containing the open is isolated, repair or replace the machine harness.

Expected Result:

The resistance measurement is between 55 and 65 ohms.

Results:

• OK - The resistance measurement is correct. Proceed to Test Step 7.

• NOT OK - The resistance measurement is greater than 65 ohms. If the resistance is approximately 115 to 125 ohms. There is an open in the harness.

  Repair: Repair or replace the machine harness.

  Proceed to Test Step 7.

• NOT OK - The resistance measurement is less than 55 ohms.

  Repair: Look for the source of the short by disconnecting the terminating resistors and check the resistance again. If the resistance is still under 55 ohms, continue disconnecting ECM modules and devices from the CAN circuit until the resistance goes up. If everything is disconnected from the CAN circuit, and the resistance still is less than 55 ohms the harness has failed.Repair or replace the machine harness.

  Proceed to Test Step 7.

Test Step 7. CHECK THE STATUS OF THE DIAGNOSTIC CODE

1. Perform a 45 N (10 lb) pull test on each of the wires that are associated with the data link circuit.

2. Reconnect all harness connectors. Verify the following:
   • The connectors are fully seated.

   • The clips for each connector are fastened completely.

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

4. Operate the machine.

5. Check the status of the CID 0247 FMI 09 diagnostic code.

Expected Result:

The CID 0247 FMI 09 diagnostic code is not active.

Results:

• OK - The CID 0247 FMI 09 diagnostic code is not active. The initial diagnostic code may have been caused by a poor connection or a short at one of the connectors that were disconnected and reconnected.

  Repair: Resume normal operation.

  STOP

• NOT OK - The CID 0247 FMI 09 diagnostic code is active. The diagnostic code has not been corrected.

  Repair: Check the circuit again. Perform a Wiggle Test on the machine wiring harness with the Cat Electronic Technician (ET) service tool. The Wiggle Test can detect the following machine wiring harness:

  • Momentary shorts

  • Intermittent shorts

  • Opens

  If the cause of the problem is not found, one of the ECM modules may have failed. The ECM that activated the diagnostic code may have failed. Prior to replacing an ECM, always contact the Technical Communicator at your dealership for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the diagnostic code is not found, replace the ECM that activated the diagnostic code. Refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".

  STOP