3500B and 3500B High Displacement Generator Set Engines Caterpillar

The CAT Data Link is a pair of twisted wires that are used for communication between electronic modules. The engine's Electronic Control Module (ECM) communicates with the electronic monitoring system over the CAT Data Link. The CAT Data Link is used to share status and diagnostic information with the Caterpillar Electronic Technician (ET). The CAT Data Link is used to program the ECM. The CAT Data Link is used to troubleshoot the ECM.

The engine can be programmed by using flash programming over the CAT Data Link.

Illustration 1	g01023101
Typical example

Test Step 1. Check for Connector Damage.

1. Turn the ECS to the OFF/RESET position.

2. Turn the battery disconnect switch to the OFF position.

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

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

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

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

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

Expected Result:

All connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.

Results:

• OK - The connectors and wiring are okay. Proceed to Test Step 2.

• Not OK - The connectors and/or wiring are not okay.

  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 CAT ET.

2. Turn the battery disconnect switch to the ON position.

3. Turn the ECS to the STOP position on engines with the "EMCP II+" panel. Turn the ECS to the SERVICE position on engines with the "EMS II" panel.

4. Check for any logged diagnostic codes.

5. Start the engine and read the status information on CAT ET.

6. Observe the engine oil pressure and the coolant temperature on the electronic monitoring system.

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

Expected Result:

The CAT ET displays the status information. The electronic monitoring system displays 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 the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".

  Stop.

• No Parameter Displayed. - There is a problem with the CAT Data Link. Proceed to Test Step 3.

• Service Tool Did Not Power Up. - The CAT ET or the communication adapter did not power up. Proceed to Test Step 4.

Test Step 3. Check the Operation of the ET.

Verify proper operation of CAT ET on another engine.

Expected Result:

CAT ET and the communications adapter worked on another engine.

Results:

• OK - CAT ET and the communications adapter did work on another engine. Proceed to Test Step 5.

• Not OK - CAT ET and the communications adapter did not work on another engine. There is a problem with CAT ET, cables, or the communication adapter.

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

  Stop.

Test Step 4. Check for the Battery Voltage.

1. Ensure that all connectors are connected.

2. Turn the ECS to the STOP position on engines with the "EMCP II+" panel. Turn the ECS to the SERVICE position on engines with the "EMS II" panel.

3. Measure the voltage between pin A and pin B at J60.

4. Turn the ECS to the OFF/RESET position.

Expected Result:

The voltage is 24 ± 3 VDC.

Results:

• OK - The voltage is 24 ± 3 VDC.

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

  Stop.

• Not OK - The voltage is not 24 ± 3 VDC. There is a problem in the harness or electrical power supply.

  Repair: Check the harness between the service tool connector and the "ECMCB". Check the "ECMCB" for proper operation.

  Stop.

Test Step 5. Check for Shorts in the Harness

1. Turn the ECS to the OFF/RESET position.

2. Turn the battery disconnect switch to the OFF position.

3. Disconnect the ECM connectors J1/P1. Disconnect the service tool connector J60/P60. Disconnect connector J99/P99 of the electronic monitoring system. Disconnect any other devices that are attached to the CAT Data Link.

4. Ensure that the connector J3A/P3A is connected.

5. Measure resistance from P1-3 to P1-9.

6. Check the resistance at the following points on ECM connector P1:
   • P1-3 to P1-5

   • P1-9 to P1-5

   • P1-3 to P1-6

   • P1-3 to P1-4

   • P1-9 to P1-4

   • P1-3 to P1-11

   • P1-9 to P1-11

7. Measure the resistance from P99-5 to P99-14.

Expected Result:

Resistance is 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 6.

• 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 6. Check the Resistance through the Harness.

1. Turn the ECS to the OFF/RESET position.

2. Turn the battery disconnect switch to the OFF position.

3. Disconnect the ECM connectors J1/P1. Disconnect the service tool connector J60/P60 and the monitoring system J99/P99. Disconnect any other devices that are attached to the CAT Data Link.

4. Ensure that the customer connector J3 /P3 is connected.

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

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

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

Expected Result:

Resistance reads less than 5 Ohms through the wires.

Results:

• OK - Resistance is less than 5 Ohms through the harness and connectors. Proceed to Test Step 7.

• Not OK - Resistance is greater than 5 Ohms. 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 7. Verify the CAT Data Link.

1. Turn the ECS to the OFF/RESET position.

2. Reconnect all of the connectors.

3. Turn the ECS to the STOP position on engines with the "EMCP II+" panel. Turn the ECS to the SERVICE position on engines with the "EMS II" panel.

4. Observe the parameters on the monitoring system.

   Note: The CAT Data Link is operating correctly at this time. If some of the parameters, 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 communications between the monitoring system and 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.

Expected Result:

The parameters appear on the electronic monitoring system.

Results:

• OK - The parameters are available for viewing on the CAT ET.

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

  Stop.

• Not OK - The parameters are not available for viewing onCAT ET.

  Repair: There is a problem with the electronic monitoring system and/or the data link cable. Check that the cable is not too long. Refer to Service Manual, SENR6587.

  Stop.