3500B Engines for 5130B and 5230B Excavators Caterpillar

There are two switches in the Ground Level Shutdown circuit. One switch is mounted beside the ladder on the machine platform. The other switch is mounted in the engine compartment. The ECM monitors the two switch inputs from the ground level shutdown circuit at all times. To shut down the engine, lift the red cover guard and toggle the ground level shutdown switch to the SHUTDOWN position. The ECM will disable the fuel injection after the switch inputs reverse states for a period of one second. The ECM remains active. The ET can be used to communicate with the ECM.

If the switch is in the SHUTDOWN position the ECM will not allow the engine to start. The ground level shutdown switch must be returned to the RUN position and the keyswitch must be cycled to the OFF/RESET position before the ECM will allow the engine to start.

The voltage at the ECM pin P1-34 of the ground level shutdown switch should be 11.5 ± 0.5 VDC when the ground level shutdown switch is in the RUN position. The voltage at the ECM pin P1-28 of the ground level shutdown switch should be less than 0.5 VDC when the ground level shutdown switch is in the RUN position.

Illustration 1	g00814279
Typical schematic

Test Step 1. Check for Connector Damage.

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the keyswitch to the OFF position.

3. Disconnect the main power.

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

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

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

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

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

Expected Result:

The connectors and wiring should be free of the following problems: damage, corrosion, abrasion and incorrect attachment.

Results:

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

• Not OK - The connectors and/or wiring need repair.

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

  Stop.

Test Step 2. Check the Status of the Ground Level Shutdown Switch on the ET.

1. Install the ET to the service tool connector.

2. Turn the keyswitch to the ON position. The engine should be off.

3. Monitor the status of the ground level shutdown switch on the ET with the switch in the RUN position.

4. Operate the ground level shutdown switch by changing the switch position to the SHUTDOWN position. Monitor the status for the ground level shutdown switch on the ET.

Expected Result:

The status of the ground level shutdown switch should read "OFF" when the ground level shutdown switch is in the RUN position. The status of the ground level shutdown switch should read "ON" with the ground level shutdown switch in the SHUTDOWN position.

Results:

• OK - The status of the ground level shutdown switch reads "ON" with the ground level shutdown switch in the SHUTDOWN position. The status of the ground level shutdown switch reads "OFF" when the ground level shutdown switch is in the RUN position.

  Repair: The circuit for the ground level shutdown switch is operating correctly.

  Stop.

• Not OK - The status of the ground level shutdown switch does not read "OFF" when the ground level shutdown switch is in the RUN position. The status of the ground level switch does not read "ON" with the ground level shutdown switch in the SHUTDOWN position. The circuit for the ground level shutdown switch is not operating correctly. Proceed to test step 3.

Test Step 3. Short the Ground Level Shutdown Switch at the ECM.

1. Disconnect the ECM connector J1/P1.

2. Remove wire F709-BU from P1-34 at ECM connector P1. Remove wire F708-YL from P1-28 at ECM connector P1. Remove wire 998-BR from P1-29 at ECM connector P1. Use a 151-6320 Wire Removal Tool .

3. Insert a jumper wire with socket terminals at each end into the connector P1 on pins P1-28 and P1-29.

4. Reconnect all the connectors.

5. Turn the keyswitch to the ON position. The engine should be off.

   Note: The digital return will no longer be connected to the other sensors and switches. Additional diagnostic codes will be generated from the ECM. Clear the codes after you complete this test.

6. Monitor the status of the ground level shutdown switch on the ET.

7. Turn the keyswitch to the OFF/RESET position.

8. Disconnect the ECM connector J1/P1.

9. Remove the wire short.

10. Insert a jumper wire with socket terminals at each end into the ECM connector P1 on pins P1-34 and P1-29.

11. Reconnect all of the connectors.

12. Turn the keyswitch to the ON position. The engine should be off.

13. Observe the status of the ground level shutdown switch on the ET.

14. Turn the keyswitch to the OFF/RESET position.

15. Remove the wire short and replace all wires.

Expected Result:

The status should read "OFF" when the wire short is inserted between pins P1-28 and P1-29. The status should read "ON" when the wire short is inserted between pins P1-34 and P1-29.

Results:

• OK - The status reads "OFF" when the wire short is inserted between pins P1-28 and P1-29. The status reads "ON" when the wire short is inserted between pins P1-34 and P1-29. The status is correct on the ET. Proceed to test step 4.

• Not OK - The status does not read "OFF" when the wire short is inserted between pins P1-28 and P1-29. The status does not read "ON" when the wire short is inserted between pins P1-34 and P1-29. The status is incorrect on the ET.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".

  Stop.

Test Step 4. Check for an Open Circuit in the Wires that go to the Engine Shutdown Switch.

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

2. Disconnect ECM connector J1/P1.

3. Install a jumper wire at the engine shutdown switch between wire F708-YL on terminal 3 and wire F709-BU on terminal 1.

4. Measure the resistance at ECM connector P1 between P1-34 and P1-28.

5. Remove the wire short.

Expected Result:

The resistance should measure less than 10 Ohms with the short in place.

Results:

• OK - The resistance measures less than 10 Ohms. Proceed to test step 5.

• Not OK - The resistance measures more than 10 Ohms.

  Repair: There is excessive resistance in the wiring between the ECM and the engine shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 5. Check for a Short in the Wires to the Engine Shutdown Switch.

1. Disconnect the wire F708-YL on terminal 3 and the wire F709-BU on terminal 1 from the engine shutdown switch.

2. Measure the resistance at ECM connector P1 between pins P1-34, P1-28 and the engine ground.

Expected Result:

The resistance should measure more than 20,000 Ohms.

Results:

• OK - The resistance measures more than 20,000 Ohms. Proceed to test step 6.

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

  Repair: There is a short in the wiring between the ECM and the engine shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 6. Check for an Open in the Wires to the Ground Level Switch.

1. Install a jumper wire at the ground level shutdown switch between the wire F709-BU on terminal 1 and the wire 998-BR on terminal 2.

2. Measure the resistance at ECM connector P1 between pins P1-34 and P1-29.

3. Remove the wire short.

Expected Result:

The resistance should measure less than 10 Ohms with the short in place.

Results:

• OK - The resistance measures less than 10 Ohms. Proceed to test step 7.

• Not OK - The resistance measures more than 10 Ohms.

  Repair: There is excessive resistance in the wiring between the ECM and the ground level shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 7. Check for a Short in the Wires to the Ground Level Shutdown Switch.

1. Disconnect the wire F709-BU on terminal 1 and the wire 998-BR on terminal 2 from the ground level shutdown switch.

2. Measure the resistance at ECM connector P1 between pins P1-34, P1-29 and the engine ground.

Expected Result:

The resistance should measure more than 20,000 Ohms.

Results:

• OK - The resistance measures more than 20,000 Ohms. Proceed to test step 8.

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

  Repair: There is a short in the wiring between the ECM and the ground level shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 8. Check the Wire between the Engine Shutdown Switch and the Ground Level Shutdown Switch for an Open.

1. Disconnect the wire F709-BU on terminal 1 and the wire G701-BU on terminal 2 from the engine shutdown switch.

2. Install a jumper wire at the engine shutdown switch between the wire F709-BU and the wire G701-BU.

3. Disconnect the wire F709-BU on terminal 1 and the wire G701-BU on terminal 3 from the ground level shutdown switch.

4. Measure the resistance between wire F709-BU and wire G701-BU at the ground level shutdown switch.

5. Remove the wire short.

Expected Result:

The resistance should measure less than 10 Ohms with the short in place.

Results:

• OK - The resistance measures less than 10 Ohms with the short in place. Proceed to test step 9.

• Not OK - The resistance measures more than 10 Ohms with the short in place.

  Repair: There is excessive resistance in the wiring between the engine shutdown switch and the ground level shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 9. Check the Wire between the Engine Shutdown Switch and the Ground Level Shutdown Switch for a Short.

1. Measure the resistance at the ground level shutdown switch between wire F709-BU and the engine ground.

2. Measure the resistance at the ground level shutdown switch between wire G701-BU and the engine ground.

Expected Result:

The resistance should measure more than 20,000 Ohms.

Results:

• OK - The resistance measures more than 20,000 Ohms. Proceed to test step 10.

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

  Repair: There is a short in the wiring between the engine shutdown switch and the ground level shutdown switch. Repair the wiring and/or connectors. Reinstall all wires and connectors. Retest the circuit for proper operation.

  Stop.

Test Step 10. Check the Engine Shutdown Switch and the Ground Level Shutdown Switch for Proper Operation.

1. Record the position of the wires on the shutdown switch before removing the wires.

2. Disconnect the wires from the shutdown switch.

3. Measure the resistance between terminal 2 and 3 of the shutdown switch with the switch in the RUN position. Toggle the switch to the SHUTDOWN position. Measure the resistance.

Expected Result:

With the switch in the RUN position, the resistance should be less than 10 Ohms. With the switch in the SHUTDOWN position, the resistance should be greater than 20,000 Ohms.

Results:

• OK - With the switch in the RUN position, the resistance measures less than 10 Ohms. With the switch in the SHUTDOWN position, the resistance was greater than 20,000 Ohms. Proceed to test step 11.

• Not OK - With the switch in the RUN position, the resistance measures more than 10 Ohms. With the switch in the SHUTDOWN position, the resistance was less than 20,000 Ohms.

  Repair: Replace the switch. Reinstall all wires and connectors.

  Stop.

Test Step 11. Check the Engine Shutdown Switch and the Ground Level Shutdown Switch for Proper Operation.

1. Record the position of the wires on the shutdown switch before removing the wires.

2. Disconnect the wires from the shutdown switch.

3. Measure the resistance between terminal 2 and terminal 1 with the switch in the RUN position. Toggle the switch to the SHUTDOWN position. Measure the resistance.

Expected Result:

With the switch in the SHUTDOWN position, the resistance should measure less than 10 Ohms. With the switch in the RUN position, the resistance should be greater than 20,000 Ohms.

Results:

• OK - With the switch in the SHUTDOWN position, the resistance measures less than 10 Ohms. With the switch in the RUN position, the resistance was greater than 20,000 Ohms.

  Repair: The wiring and the switches in the circuit appear to be operating correctly. Reinstall all wires and connectors. There may be an intermittent problem. Inspect the wiring and the connectors for problems. Refer to Troubleshooting, "Inspecting Electrical Connectors" for details.

  Stop.

• Not OK - With the switch in the SHUTDOWN position, the resistance measures more than 10 Ohms. With the switch in the RUN position, the resistance was less than 20,000 Ohms.

  Repair: Replace the switch. Reinstall all wires and connectors.

  Stop.