3500B Locomotive Engines Caterpillar

The CAT Data Link is used for communication between electronic modules. The CAT Data Link is used to communicate information from the ECM to the Caterpillar Monitoring System. The CAT Data Link is used for programming and troubleshooting the ECM.

The ECM communicates with the Caterpillar Monitoring System in order to share engine information and electronic system diagnostics.

The ECM communicates with an Electronic Service Tool in order to share status and diagnostic information. The Electronic Service Tool can also be used to configure the ECM parameters on the engine. This information will not be available if communications fail between the ECM and the Electronic Service Tool.

Illustration 1	g00848568

Test Step 1. Check for Connector Damage.

1. Disconnect the main power.

2. Thoroughly inspect the ECM connectors J1/P1 and J2/P2. Inspect all of the other connectors. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.

4. Check the ECM connector (allen head screw) for the proper torque of 6.0 N·m (55 lb in).

5. Check the customer connector (allen head screw) for the proper torque of 2.25 ± 0.25 N·m (20 ± 2 lb in).

6. Check the harness and the wiring for abrasion and pinch points.

Expected Result:

Check the connectors and wiring for the following problems: damage, corrosion, abrasion and incorrect attachment.

Results:

• OK - The connectors and wiring are okay. Proceed to test step 2.

• Not OK -

  Repair: Repair the connector and/or wiring or replace the connector and/or wiring.

  Stop.

Test Step 2. Check the CAT Data Link.

1. Connect the ET to the service tool connector.

2. Connect main power.

3. Check for any LOGGED diagnostic codes.

4. Start the engine and read the Status Information on the Electronic Service Tool.

5. Observe the engine oil pressure and the coolant temperature on the Caterpillar Monitoring System.

6. Shut down the engine.

   Note: If some of the parameter, but not all of the parameters were displayed, the CAT Data Link is OK. Check the component that is associated with any missing parameter.

Expected Result:

The Electronic Service Tool should display the status Information. The Caterpillar Monitoring System should display engine parameters.

Results:

• OK - The CAT Data Link is operating correctly at this time.

  Repair: The problem may be intermittent. If the problem is intermittent refer to Troubleshooting, "Inspecting Electrical Connectors".

  Stop.

• Not OK - There is a problem with the CAT Data Link. Proceed to test step 6.

• Service Tool Did Not Power Up - The Electronic Service Tool or the Communication Adapter did not power up. Proceed to test step 3.

Test Step 3. Check Battery Voltage.

1. Disconnect main power.

2. Disconnect the ET and the Communication Adapter Tool from the service tool connector.

3. Ensure that all connectors are connected.

4. Connect main power.

5. Measure the voltage between pin-A and pin-B at the service tool connector J60.

Expected Result:

The voltage should be 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC. Proceed to test step 4.

• Not OK - The voltage is not 24 ± 3 VDC.

  Repair: Check the electrical power supply to the CAT Data Link. Check the wiring from the electrical supply to the service tool connector J60.

  Stop.

Test Step 4. Check for Shorts In the Harness

1. Disconnect main power.

2. Disconnect the ECM connectors J1/P1 and J2/P2. Disconnect the service tool connector J60/P60. Disconnect the Caterpillar Monitoring System. Disconnect any other modules that are connected to the CAT Data Link.

3. Measure resistance at the ECM connector from P1-3 to P1-9.

4. Check the resistance at the following points:
   • P1-3 to P1-5

   • P1-9 to P1-5

   • P1-3 to P1-6

   • P1-9 to P1-6

   • P1-3 to P1-4

   • P1-9 to P1-4

   • P1-3 to P1-11

   • P1-9 to P1-11

Expected Result:

Resistance should read more than 20,000 Ohms for each measurement.

Results:

• OK - The resistance is greater than 20,000 Ohms. The harness is free of shorts. Proceed to test step 5.

• Not OK - The resistance is less than 20,000 Ohms.

  Repair: Repair the connector and/or wiring or replace the connector and/or wiring.

  Stop.

Test Step 5. Check the Resistance through the Harness.

1. Disconnect main power.

2. Disconnect the ECM connectors J1/P1 and J2/P2. Disconnect the service tool connector J60/P60. Disconnect the Caterpillar Monitoring System. Disconnect any other modules that are connected to the CAT Data Link.

3. Ensure that the customer connector "A" is connected.

4. Use a suitable piece of wire to short P1-9 to P1-3.

5. Measure the resistance between P99-14 to P99-5.

6. Measure the resistance between pin-D and pin-E of the Service Tool Connector J60.

Expected Result:

Resistance should read less than 10 Ohms through the wires.

Results:

• OK - Resistance is less than 10 Ohms through the harness and connectors. Proceed to test step 7.

• Not OK - There is an open circuit in the harness or connectors.

  Repair: Repair the connector and/or wiring or replace the connector and/or wiring.

  Stop.

Test Step 6. Check the Operation of the Electronic Service Tool.

1. Verify proper operation of the Electronic Service Tool and Communication Adapter on another engine.

Expected Result:

The ET should be able to communicate with another engine.

Results:

• OK - The Electronic Service Tool was able to communicate with another engine. Proceed to test step 4.

• Not OK - The Electronic Service Tool and the Communications Adapter did not work on another engine. There is a problem with the Electronic Service Tool, cables, or the Communication Adapter.

  Repair: Operating Manual, SEHS9264.

  Stop.

Test Step 7. Check Isolated Communication.

1. Disconnect main power.

2. Connect ECM connectors J1/P1, and J2/P2.

3. Disconnect the connector J99/P99 for the Caterpillar Monitoring System. Disconnect all other modules that are connected to the CAT Data Link.

4. Connect the ET to the service tool connector J60.

5. Connect main power.

6. Read LOGGED Diagnostics.

7. Start the engine.

8. Read the Status information.

Expected Result:

The Electronic Service Tool should display any Diagnostics and Status Information.

Results:

• OK - The Electronic Service Tool is displaying data. Proceed to test step 8.

• Not OK - The Electronic Service Tool is not displaying data. Proceed to test step 6.

Test Step 8. Verify the CAT Data Link.

1. Disconnect main power.

2. Reconnect all of the connectors.

3. Connect main power.

4. Observe the parameters on the Monitoring System.

   Note: The CAT Data Link is operating correctly at this time. If some of the parameter, but not all of the parameters were displayed, the CAT Data Link is okay. Check the component that is associated with any missing parameter.

   Note: The Monitoring System can display a message that indicates a fault with the ECM. The message may not indicate that the ECM is faulty. The message is displayed when the system no longer receives any engine related parameters.

   Note: The Caterpillar Monitoring System is optional for this engine. The Caterpillar Monitoring System may not be installed.

Expected Result:

The parameters should appear on the Caterpillar Monitoring System.

Results:

• OK - The parameters appear on the status screen.

  Repair: The problem may be intermittent. If the problem is intermittent refer to Troubleshooting, "Inspecting Electrical Connectors".

  Stop.

• Not OK - The parameters do not appear on the status screen.

  Repair: There is a problem with the Caterpillar Monitoring System and/or the data link cable. Refer to Tool Operating Manual, SEHS9264.

  Stop.