3176C Engines for Caterpillar Built Machines Caterpillar

Use this procedure if you suspect that there is a problem with the circuit for the user defined shutdown switch.

The user defined shutdown can be connected to any electronic switch or to any mechanical switch in the electrical system that would shut down the engine for any reason. When the signal is grounded, an event code is logged in memory and the Electronic Control Module (ECM) disables injection.

The input must be pulled below 0.5 VDC before the ECM will recognize the shutdown signal. Prior to the enabling of the user defined shutdown by the ECM, certain events may be required to be satisfied by the operator. Examples of these events would include engagement of the parking brake or a machine ground speed of zero. Refer to the machine's Operation and Maintenance Manual for the specific events that apply.

Illustration 1	g01277105
Schematic

Test Step 1. Inspect Electrical Connectors and Wiring

1. Remove the electrical power from the ECM.

2. Thoroughly inspect the J1/P1 ECM connector and the connection to the user defined shutdown device (customer shutdown switch). Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

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Illustration 2	g01120572
P1 ECM connector (P1-59) User defined shutdown input

3. Perform a 45 N (10 lb) pull test on the wire in the ECM connector that is associated with the active event code.

4. Check the allen head screw for each ECM connector for the proper torque. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.

5. Check the harness and wiring for abrasion and for pinch points from the user defined shutdown device to the ECM.

Expected Result:

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

Results:

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

• Not OK - There is a problem in the connectors and/or wiring.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.

  STOP

Test Step 2. Check the Status of the User Defined Shutdown Input on Caterpillar Electronic Technician (ET)

1. Verify that the customer shutdown switch is in the OPEN position.

2. Connect Cat ET to the service tool connector.

3. Restore the electrical power to the ECM.

4. Observe the status of "User Shutdown" on Cat ET.

5. Switch the customer shutdown switch to the CLOSED position.

6. Observe the status of "User Shutdown" on Cat ET.

7. Remove the electrical power from the ECM.

Expected Result:

The status of the "User Shutdown" is "OFF" when the switch is in the OPEN position. The status of the "User Shutdown" is "ON" when the switch is in the CLOSED position.

Results:

• OK - The status of the "User Shutdown" is correct.

  Repair: There may be an intermittent problem. The problem may have been related to a faulty connection in the harness or in a connector. Carefully reinspect the connectors and wiring. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

  STOP

• Not OK - The status of the "User Shutdown" is not correct for one of the switch positions. Proceed to Test Step 3.

Test Step 3. Check the Harness between the Customer Shutdown Switch and the ECM

1. Remove the electrical power from the ECM.

2. Disconnect the signal wire from the customer shutdown switch.

3. Restore the electrical power to the ECM.

4. Observe the status of "User Shutdown" on Cat ET.

5. Use a suitable piece of wire to short the signal wire at the switch to chassis ground.

6. Observe the status of "User Shutdown" on Cat ET.

Expected Result:

The status of the "User Shutdown" is "OFF" when the wire is not shorted to chassis ground. The status of the "User Shutdown" is "ON" when the wire is shorted to chassis ground.

Results:

• OK - The circuit for the "User Shutdown" is operating correctly. The harness wiring and ECM are OK.

  Repair: Replace the customer shutdown switch.

  STOP

• Not OK - The status of the "User Shutdown" was not correct for one of the test procedures. Proceed to Test Step 4.

Test Step 4. Check the Operation of the ECM

1. Remove the electrical power from the ECM.

2. Disconnect the J1/P1 ECM connector. Remove terminal P1-59 from the ECM connector.

3. Fabricate a jumper wire that is long enough to connect from a terminal at the ECM connector to chassis ground. Crimp a connector terminal to one end of the jumper wire.

4. Connect the J1/P1 ECM connector.

5. Restore the electrical power to the ECM.

6. Observe the status of "User Shutdown" on Cat ET.

7. Short the jumper wire in P1-59 to chassis ground.

8. Observe the status of "User Shutdown" on Cat ET.

Expected Result:

The status of the "User Shutdown" is "OFF" when the jumper wire is not shorted to chassis ground. The status of the "User Shutdown" is "ON" when the jumper wire is shorted to chassis ground.

Results:

• OK - The ECM is responding to the input correctly.

  Repair: Repair the connectors or wiring and/or replace the connectors or wiring between the ECM and the customer shutdown switch.

  STOP

• Not OK - The status of the "User Shutdown" is not correct.

  Repair: Verify your results. Replace the ECM. Refer to electronic troubleshooting Troubleshooting, "Replacing the ECM" before replacing the ECM.

  STOP